Treatment of peripheral t cell lymphoma

ABSTRACT

The present disclosure relates to methods for the treatment, prevention and diagnosis of peripheral T-cell lymphoma using compounds that specifically bind NKp46. Included in particular are compounds that bind NKp46 and deplete tumor cells that express NKp46 at their surface, and pharmaceutical compositions comprising the same. The disclosure also relates to the use of antibodies that specifically bind NKp46 in diagnostic and theranostic assays in the detection and treatment of peripheral T-cell lymphoma.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/767,600, filed Aug. 13, 2015, now U.S. Pat. No. 10,344,087, which isthe U.S. national stage application of International Patent ApplicationNo. PCT/EP2014/052849, filed Feb. 13, 2014, which claims the benefit ofU.S. Provisional Application No. 61/764,639, filed Feb. 14, 2013, andU.S. Provisional Application No. 61/831,792, filed Jun. 6, 2013, thedisclosures of which are incorporated herein by reference in theirentirety, including any drawings.

REFERENCE TO SEQUENCE LISTING

The present application is being filed along with a Sequence Listing inelectronic format. The Sequence Listing is provided as a file entitled“NKp46-2 PCT_ST25”, created 12 Feb. 2014, which is 3 KB in size. Theinformation in the electronic format of the Sequence Listing isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to the use of NKp46-targeting agents for thediagnosis and treatment of aggressive lymphomas.

BACKGROUND OF THE INVENTION

NK cell activity is regulated by a complex mechanism that involves bothactivating and inhibitory signals. Several distinct NK-specificreceptors have been identified that play an important role in the NKcell-mediated recognition and killing of HLA Class I deficient targetcells. Natural Cytotoxicity Receptors (NCR) refers to a class ofactivating receptor proteins, and the genes expressing them, that arespecifically expressed in NK cells. Examples of NCRs include NKp30,NKp44, and NKp46 (see, e.g., Lanier (2001) Nat Immunol 2:23-27, Pende etal. (1999) J Exp Med. 190:1505-1516, Cantoni et al. (1999) J Exp Med.189:787-796, Sivori et al (1997) J Exp Med. 186:1129-1136, Pessino etal. (1998) J Exp Med. 188(5):953-60, and Mandelboim et al. (2001) Nature409:1055-1060, the entire disclosures of which are herein incorporatedby reference). These receptors are members of the Ig superfamily, andtheir cross-linking, induced by specific mAbs, leads to a strong NK cellactivation resulting in increased intracellular Ca⁺⁺ levels, triggeringof cytotoxicity, and lymphokine release, and an activation of NKcytotoxicity against many types of target cells. The expression of NCRs,and NKp46 in particular, is reported as limited to NK cells.

Peripheral T-cell non-Hodgkin's lymphomas (PTCLs) account for 15% to 20%of aggressive lymphomas and 7% to 10% of all the non-Hodgkin's lymphomas(NHLs) in Western countries. They usually occur in middle-aged toelderly patients, and presenting features are characterized by adisseminated disease in 68% of the patients, with systemic symptoms innearly half of them (45%), bone marrow (BM) involvement in a quarter(25.8%), and extranodal disease in a third (37%). Despite aggressivetherapy, more than half the patients die of their disease. While certaindistinctive disease entities have improved prognostics if treated, theprognosis for many aggressive PTCLs remains relatively unchanged by theuse of second- and third-generation chemotherapy regimens and 5-yearoverall survival (OS) still remains between 25% and 47% for PTCL-NOS,for example.

Consequently, there is a need in the art for improved benefit topatients having PTCLs.

SUMMARY OF THE INVENTION

The present inventors have discovered that NKp46 is expressed onperipheral T-cell lymphomas (PTCLs), particularly non-cutaneous PTCLs.In NKp46-positive PTCLs, NKp46 is expressed on the cell surface and atlevels sufficient to permit targeting with NKp46-binding antibodies(e.g., as assessed by immunohistochemistry). NKp46 is expressed on fewother tissues (only on a small fraction of NK cells), permitting NKp46to serve as a marker and target for the detection and treatment ofperipheral T-cell lymphomas, particularly aggressive and/or advancedT-cell lymphomas, e.g., aggressive and/or advanced nodal or extranodalperipheral T-cell lymphomas. Accordingly, in one embodiment, a method isprovided for treating or preventing a peripheral T-cell lymphoma in anindividual, the method comprising administering to an individual atherapeutically active amount of a compound that binds an NKp46polypeptide. In one aspect a composition is provided comprising acompound that binds an NKp46 polypeptide, for use in the treatment orprevention of peripheral T-cell lymphoma. In one aspect the compoundthat binds an NKp46 polypeptide is a compound that depletes a cell thatexpresses NKp46 at its surface, e.g., a PTCL cell that expresses NKp46.In one aspect the compound is a depleting anti-NKp46 antibody. In oneembodiment a compound is provided that binds an NKp46 polypeptide anddepletes NKp46-expressing tumor cells, for use in the treatment orprevention of a PTCL in an individual. Optionally said treatment orprevention comprises administration of a compound that binds an NKp46polypeptide to an individual having a PTCL. In one embodiment of any ofthe therapeutic uses or PTCL treatment or prevention methods herein, theindividual has an NK/T-lymphoma. In one embodiment of any of thetherapeutic uses or PTCL treatment or prevention methods herein, theindividual has an enteropathy-associated T-cell lymphoma (EATL). In oneembodiment of any of the therapeutic uses or PTCL treatment orprevention methods herein, the individual has an anaplastic large celllymphoma (ALCL). In one embodiment of any of the therapeutic uses orPTCL treatment or prevention methods herein, the individual has aPTCL-NOS. In one embodiment of any of the therapeutic uses or PTCLtreatment or prevention methods herein, the treatment or prevention of aPTCL (e.g., an EATL, an ALCL, or a PTCL-NOS) in an individual comprises:

a) determining the NKp46 polypeptide status of malignant cells withinthe individual having a PTCL, and

b) upon a determination that the patient that an NKp46 polypeptideprominently expressed on the surface of malignant cells, administeringto the individual said compound that binds an NKp46 polypeptide.

In one embodiment of any the treatment methods or uses herein, NK/Tlymphoma, nasal type, is treated, and the method does not require (e.g.,is free of, or does not use, or does not comprise) a step of:determining the NKp46 polypeptide status of malignant cells within theindividual having a PTCL prior to administration of a compound thatbinds an NKp46 polypeptide.

Additionally, it has been found that patients having more advanced PTCLshave acquired NKp46 expression while PTCLs at earlier stages may beNKp46-negative. Accordingly, in one embodiment, a method is provided fortreating an individual having an advanced (e.g., stage IV or higher)peripheral T-cell lymphoma, the method comprising administering to theindividual a therapeutically active amount of a compound that binds anNKp46 polypeptide.

In another embodiment a method is provided combining an NKp46 detectionstep to identify patients having NKp46+ tumors; these patients canthereafter be treated with an NKp46-binding agent. Such method permitsNKp46 therapy to be directed to suitable patients without reliance on adisease staging. Such method also helps permit the prevention ofadvanced PTCL (e.g., prevention of progressing of PTCL to an advancedstage, e.g., stage IV) because patients can be treated as NKp46 appears.In particular, since not all patients have tumors that are positive forNKp46 expression, the method has the advantage of permitting selectionof individual patients having tumors that are expected to be responsiveto treatment with a compound that binds an NKp46 polypeptide.

In a further aspect, it has been found that patients with NKp46-positivePTCL-NOS can have tumors that are CD30-negative (tumor cells do notexpress CD30 on their surface). Thus, methods are provided of treating aCD30-negative PTCL, e.g., a PTCL-NOS, comprising administering acompound that binds an NKp46 polypeptide to a patient having aCD30-negative PTCL. In another embodiment of treating an individualhaving a PTCL, the method comprises administering a compound that bindsan NKp46 polypeptide to an individual having a PTCL who is refractive totreatment with an anti-CD30 antibody. In other embodiments, when PTCLsare CD30-positive (e.g., anaplastic large cell lymphomas which broadlyexpress CD30, certain PTCL-NOS), a compound that binds an NKp46polypeptide can be administered in combination with an anti-CD30antibody (e.g., a depleting anti-CD30 antibody, for example an anti-CD30antibody linked to a toxic moiety).

In one embodiment, a method is provided for detecting a peripheralT-cell lymphoma in an individual, the method comprising detecting anNKp46 nucleic acid or polypeptide in a biological sample (e.g., on acell) from an individual. In one embodiment, a method is provided fordetecting an aggressive or advanced (e.g., stage IV or higher)peripheral T cell lymphoma in an individual, the method comprisingdetecting an NKp46 nucleic acid or polypeptide in a biological sample(e.g., on a cell) from an individual. A determination that a biologicalsample expresses NKp46 indicates that the patient has a peripheralT-cell lymphoma (or advanced/aggressive PTCL). In one embodiment, themethod comprises determining the level of expression of an NKp46 nucleicacid or polypeptide in a biological sample and comparing the level to areference level (e.g., a value, weak cell surface staining, etc.)corresponding to a healthy individual. A determination that a biologicalsample expresses an NKp46 nucleic acid or polypeptide at a level that isincreased compared to the reference level indicates that the patient hasa peripheral T-cell lymphoma. Optionally, detecting an NKp46 polypeptidein a biological sample comprises detecting the NKp46 polypeptideexpressed on the surface of a malignant lymphocyte.

In one embodiment, a method is provided comprising:

(a) determining whether an individual has an advanced and/or aggressiveperipheral T-cell lymphoma; and(b) if the individual has an advanced and/or aggressive peripheralT-cell lymphoma, treating the individual with a therapeutically activeamount of a compound that binds an NKp46 polypeptide.

In one embodiment, a method is provided comprising: (a) determiningwhether an individual has a peripheral T-cell lymphoma; and (b) if theindividual has a peripheral T-cell lymphoma, determining whether theindividual has peripheral T-cell lymphoma cells that express an NKp46polypeptide. The method may optionally further comprise treating theindividual with a therapeutically active amount of a compound that bindsan NKp46 polypeptide if the individual has peripheral T-cell lymphomacells that express NKp46 on their surface.

In one embodiment, a method is provided comprising:

(a) determining whether an individual has peripheral T cell lymphomacells that express an NKp46 polypeptide on their surface; and(b) if the individual has peripheral T-cell lymphoma cells that expressNKp46 on their surface, treating the individual with a therapeuticallyactive amount of a compound that binds an NKp46 polypeptide.

In one embodiment, a method is provided comprising treating anindividual having a CD30-negative PTCL. In one embodiment, the methodcomprises:

(a) determining whether an individual (e.g., an individual with advancedPTCL) has peripheral T-cell lymphoma cells that express CD30 on theirsurface, optionally further determining whether an individual hasperipheral T-cell lymphoma cells that express NKp46 on their surface;and(b) if the individual has peripheral T-cell lymphoma cells that do notexpress CD30 on their surface, optionally wherein the individual hasperipheral T-cell lymphoma cells that express an NKp46 polypeptide ontheir surface, treating the individual with a therapeutically activeamount of a compound that binds an NKp46 polypeptide.

In one embodiment, a method is provided comprising treating anindividual having a CD30-positive PTCL. In one embodiment, the methodcomprises:

(a) determining whether an individual (e.g., an individual with advancedPTCL) has peripheral T-cell lymphoma cells that express CD30 on theirsurface, and further determining whether the individual has peripheralT-cell lymphoma cells that express NKp46 on their surface; and(b) if the individual has peripheral T-cell lymphoma cells that expressCD30 on their surface, and the individual has peripheral T-cell lymphomacells that express an NKp46 polypeptide on their surface, treating theindividual with a therapeutically active amount of a compound that bindsan NKp46 polypeptide and with a therapeutically active amount of ananti-CD30 antibody.

In one embodiment of any of the methods, determining whether anindividual has peripheral T-cell lymphoma cells that express an NKp46polypeptide comprises obtaining a biological sample from the individualthat comprises peripheral T-cell lymphoma cells, bringing said cellsinto contact with an antibody that binds an NKp46 polypeptide, anddetecting whether cells express NKp46 on their surface.

Optionally, in any embodiment, determining whether an individual hasperipheral T-cell lymphoma cells that express NKp46 comprises conductingan immunohistochemistry assay. Optionally, determining whether anindividual has peripheral T-cell lymphoma cells that express NKp46comprises conducting a flow cytometry assay. Both IHC and flow cytometrycan detect surface expression of NKp46.

A method is also provided of treating a patient with a PTCL, the methodcomprising:

a) determining the NKp46 polypeptide status of malignant cells (e.g.,PTCL cells) within the patient, e.g., determining whether an NKp46polypeptide is prominently expressed on the surface of said malignantcells, and b) administering a compound to the patient that specificallybinds to an NKp46 polypeptide that is prominently expressed in saidmalignant cells (e.g., prominently expressed on the surface of malignantcells). Optionally, determining the NKp46 polypeptide status comprisesdetermining whether an NKp46 polypeptide is prominently expressed on thesurface of said malignant cells. Optionally, determining whether anNKp46 polypeptide is prominently expressed on the surface of saidmalignant cells comprises obtaining from the individual a biologicalsample that comprises peripheral T-cell lymphoma cells, bringing saidcells into contact with an antibody that binds an NKp46 polypeptide, anddetecting cells that express NKp46 (e.g., determining the number orportion of cells that express NKp46).

Preferably the compound that binds an NKp46 polypeptide is a compoundthat causes the death of an NKp46-expressing cell. Optionally, thecompound that binds an NKp46 polypeptide is a polypeptide, optionally anantibody (e.g., monoclonal antibody), that binds an NKp46 polypeptide,optionally a polypeptide or other compound that is a natural ligand ofNKp46. Optionally, the antibody is a depleting antibody. Optionally, theantibody is an antibody that directs ADCC and/or CDC toward anNKp46-expressing cell. Optionally, the compound that binds an NKp46polypeptide delivers a cytotoxic agent (e.g., small molecule) to anNKp46-expressing cell, e.g., an anti-NK46 antibody linked to a toxicmoiety.

Optionally, the compound that binds an NKp46 polypeptide is administeredbetween once daily and once per month. Optionally, the composition isadministered as monotherapy. Optionally, the composition is administeredin combination with a second therapeutic agent. Optionally, thecomposition is administered in combination with an anti-cancer agent.

In one embodiment, a method is provided of producing a composition forthe treatment of peripheral T-cell lymphoma or for use in the preventionof peripheral T-cell lymphoma in a mammalian subject, said methodcomprising the steps of: a) providing a plurality of test compositions;b) testing each compound for the ability to bind NKp46 and/or cause thedepletion of NKp46-expressing cells; and c) selecting a compound whichbinds an NKp46 polypeptide and/or causes the depletion ofNKp46-expressing cells as suitable for the treatment of peripheralT-cell lymphoma or for use in the prevention of peripheral T-celllymphoma.

Optionally, the method further comprises producing a quantity of thecompound selected in step c) and/or formulation a quantity of thecompound selected in step c) with a pharmaceutically acceptableexcipient.

Optionally, step b) further comprises testing said test composition forthe ability to direct ADCC and/or CDC toward an NKp46-expressing cell,e.g., a peripheral T-cell lymphoma cell.

In one embodiment, a method is provided comprising:

(a) determining whether an individual has a peripheral T-cell lymphoma;and

(b) if the individual has a peripheral T-cell lymphoma, treating theindividual with a therapeutically active amount of a compound that bindsan NKp46 polypeptide.

In one embodiment, determining whether an individual has a peripheralT-cell lymphoma is made according to standard medical guidelines.

In one embodiment, determining whether an individual has a peripheralT-cell lymphoma comprises identifying a population of abnormal cells orabnormal numbers of cells. Optionally, said identification is by flowcytometry. Optionally, the method further comprises sorting or isolatingthe population of abnormal cells.

In one embodiment, determining whether an individual has a peripheralT-cell lymphoma comprises detecting cytogenetic aberrations (e.g.,assessing karyotype).

In one embodiment, determining whether an individual has a peripheralT-cell lymphoma comprises sorting the population of abnormal cells, andcontacting nucleic acid isolated from the sorted cells with one or moreoligonucleotides, wherein the contacting determines the presence of aneoplastic genetic marker, thereby detecting the presence of peripheralT-cell lymphoma.

In one embodiment, determining whether an individual has a peripheralT-cell lymphoma comprises assessing the levels of a serum protein in theindividual.

Optionally, the method further comprises a step of assessing, followingtreatment with a compound that binds an NKp46 polypeptide, whether theindividual has an amelioration in peripheral T-cell lymphoma, e.g.,whether the individual has decreased numbers of peripheral T-celllymphoma cells.

In one embodiment of any aspect herein, the PTCL is an aggressive and/oradvanced PTCL. In one embodiment, the PTCL is aggressive non-cutaneousPTCL. In one embodiment, the PTCL is PTCL-NOS (also referred to asPCTL-U). In one embodiment, the PTCL is a nodal (e.g., primarily nodal)PTCL, for example a PTCL-NOS, AITL, or ALCL (ALK+ or ALK−). In oneembodiment, the PTCL is an anaplastic large cell lymphoma (ALCL),optionally an ALK-negative ALCL. In one embodiment, the PTCL is anangioimmunoblastic T-cell lymphoma (AITL), optionally a cutaneous AITL,optionally a non-cutaneous AITL. In one embodiment, a PTCL may be anaggressive, non-cutaneous, primarily nodal PCTL. In one embodiment, thePTCL is an extranodal (e.g., primarily extranodal) PTCL. In one examplea PTCL may be an aggressive, non-cutaneous, extranodal PCTL. In oneembodiment, the PTCL is an adult T-cell leukemia or lymphoma (ATL),e.g., an HTLV+ ATL. In one embodiment, the PTCL is an orthovisceralextranodal disease, e.g., NK−/T-cell lymphoma or anenteropathy-associated T-cell lymphoma. In one embodiment, the PTCL isan extranodal NK−/T-cell lymphoma, nasal type. In one embodiment, thePTCL is an enteropathy-associated T-cell lymphoma (EATL).

In one embodiment of any aspect herein, the PTCL is a CD30-positive PTCLand the anti-NKp46 antibody is administered in combination with ananti-CD30 antibody. In one embodiment of any aspect herein, the PTCL isa CD4-positive PTCL and the anti-NKp46 antibody is administered incombination with an anti-CD4 antibody.

In one embodiment of any aspect herein, the PTCL is characterized byabsence of NK cell-associated or NK-specific markers, e.g., CD56 and/orCD57. In one embodiment of any aspect herein, the PTCL is characterizedby the presence of NK cell-associated or NK-specific markers, e.g., CD56and/or CD57.

These aspects are more fully described in, and additional aspects,features, and advantages will be apparent from, the description of theinvention provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows antibody 195314 (as well as positive control rituximab)induced specific lysis of NKp46-tranfected 721.221 cells in an ADCCassay, using human KHYG-1 murine FcγRIV NK cell lines.

FIG. 2 shows staining by anti-NKp46 antibody on NK−/T-lymphoma cells.The figure additionally shows that the NKp46-positive cells expressCD183 (CXCR3), CD56 and CD54 (ICAM).

DESCRIPTION OF THE INVENTION

The identification expression of NKp46 polypeptides at the surface ofmalignant PTCL cells permits the development of therapeutic agents thatare able to directly and specifically target pathogenic cells, as wellas diagnostic agents that can be used to diagnose PTCL.

Methods are provided of using the antigen-binding compounds; forexample, a method is provided for inhibiting PTCL cell proliferation oractivity, for delivering a molecule to a PTCL cell (e.g., a toxicmolecule, a detectable marker, etc.), for targeting, identifying orpurifying a cell, for depleting, killing or eliminating a cell, or forreducing cell proliferation, the method comprising exposing a cell, suchas a PTCL cell which expresses an NKp46 polypeptide, to anantigen-binding compound that binds an NKp46 polypeptide. It will beappreciated that for the purposes herein, “cell proliferation” can referto any aspect of the growth or proliferation of cells, e.g., cellgrowth, cell division, or any aspect of the cell cycle. The cell may bein a cell culture (in vitro) or in a mammal (in vivo), e.g., a mammalsuffering from PTCL. Also provided is a method for inducing the death ofa cell or inhibiting the proliferation or activity of a PTCL cell whichexpresses an NKp46 polypeptide, comprising exposing the cell to anantigen-binding compound that binds an NKp46 polypeptide in an amounteffective to induce death and/or inhibit the proliferation of the cell.

Antibodies specific for NKp46 can be used for a range of purposes forthe diagnosis or treatment of PTCL, including purifying NKp46 orNKp46-expressing cells in patients having PTCL, suspected of having PTCLor susceptible to PTCL, targeting NKp46-expressing cells for destructionin vivo, or specifically labeling/binding NKp46 in vivo, ex vivo, or invitro, in cells of patients having PTCL, suspected of having PTCL orsusceptible to PTCL, including in methods such as immunoblotting, IHCanalysis (e.g., on frozen tissue samples from biopsies), FACS analysis,and immunoprecipitation.

Definitions

As used in the specification, “a” or “an” may mean one or more. As usedin the claim(s), when used in conjunction with the word “comprising”,the words “a” or “an” may mean one or more than one. As used herein“another” may mean at least a second or more.

Where “comprising” is used, this can optionally be replaced by“consisting essentially of” or by “consisting of”.

Whenever within this whole specification “treatment of PTCL” or the likeis mentioned with reference to an anti-NKp46 binding agent (e.g.,antibody), there is meant: (a) method of treatment of PTCL, said methodcomprising the step of administering (for at least one treatment) ananti-NKp46 binding agent (preferably in a pharmaceutically acceptablecarrier material) to an individual, a mammal, or especially a human inneed of such treatment, in a dose that allows for the treatment of PTCL(a therapeutically effective amount), preferably in a dose (amount) asspecified herein; (b) the use of an anti-NKp46 binding agent for thetreatment of PTCL, or an anti-NKp46 binding agent for use in saidtreatment (especially in a human); (c) the use of an anti-NKp46 bindingagent for the manufacture of a pharmaceutical preparation for thetreatment of PTCL, a method of using an anti-NKp46 binding agent for themanufacture of a pharmaceutical preparation for the treatment of PTCL,comprising admixing an anti-NKp46 binding agent with a pharmaceuticallyacceptable carrier, or a pharmaceutical preparation comprising aneffective dose of an anti-NKp46 binding agent that is appropriate forthe treatment of PTCL; or (d) any combination of a), b), and c), inaccordance with the subject matter allowable for patenting in a countrywhere this application is filed.

The term “biopsy” as used herein is defined as removal of a tissue forthe purpose of examination, such as to establish diagnosis. Examples oftypes of biopsies include by application of suction, such as through aneedle attached to a syringe; by instrumental removal of a fragment oftissue; by removal with appropriate instruments through an endoscope; bysurgical excision, such as of the whole lesion; and the like.

The term “antibody” as used herein refers to polyclonal and monoclonalantibodies. Depending on the type of constant domain in the heavychains, antibodies are assigned to one of five major classes: IgA, IgD,IgE, IgG, and IgM. Several of these are further divided into subclassesor isotypes, such as IgG1, IgG2, IgG3, IgG4, and the like. An exemplaryimmunoglobulin (antibody) structural unit comprises a tetramer. Eachtetramer is composed of two identical pairs of polypeptide chains, eachpair having one “light” (about 25 kDa) and one “heavy” (about 50-70 kDa)chain. The N-terminus of each chain defines a variable region of about100 to 110 or more amino acids that is primarily responsible for antigenrecognition. The terms variable light chain (V_(L)) and variable heavychain (V_(H)) refer to these light and heavy chains respectively. Theheavy-chain constant domains that correspond to the different classes ofimmunoglobulins are termed “alpha,” “delta,” “epsilon,” “gamma” and“mu,” respectively. The subunit structures and three-dimensionalconfigurations of different classes of immunoglobulins are well-known.IgG are the exemplary classes of antibodies employed herein because theyare the most common antibodies in the physiological situation andbecause they are most easily made in a laboratory setting. Optionallythe antibody is a monoclonal antibody. Particular examples of antibodiesare humanized, chimeric, human, or otherwise-human-suitable antibodies.“Antibodies” also includes any fragment or derivative of any of theherein-described antibodies.

The term “specifically binds to” means that an antibody can bindpreferably in a competitive binding assay to the binding partner, e.g.,NKp46, as assessed using either recombinant forms of the proteins,epitopes therein, or native proteins present on the surface of isolatedtarget cells. Competitive binding assays and other methods fordetermining specific binding are further described below and arewell-known in the art.

When an antibody is said to “compete with” a particular monoclonalantibody, it means that the antibody competes with the monoclonalantibody in a binding assay using either recombinant NKp46 molecules orsurface-expressed NKp46 molecules. For example, if a test antibodyreduces the binding of Bab281, 9E2 or 195314 to an NKp46 polypeptide orNKp46-expressing cell in a binding assay, the antibody is said to“compete” respectively with Bab281, 9E2 or 195314.

The term “affinity” as used herein means the strength of the binding ofan antibody to an epitope. The affinity of an antibody is given by thedissociation constant Kd, defined as [Ab]×[Ag]/[Ab-Ag], where [Ab-Ag] isthe molar concentration of the antibody-antigen complex, [Ab] is themolar concentration of the unbound antibody and [Ag] is the molarconcentration of the unbound antigen. The affinity constant K_(a) isdefined by 1/Kd. Methods for determining the affinity of mAbs can befound in Harlow, et al., Antibodies: A Laboratory Manual, Cold SpringHarbor Laboratory Press, Cold Spring Harbor, N.Y. 1988), Coligan et al.,eds., Current Protocols in Immunology, Greene Publishing Assoc. andWiley Interscience, N.Y. (1992, 1993), and Muller, Meth. Enzymol.92:589-601 (1983), which references are entirely incorporated herein byreference. One standard method well-known in the art for determining theaffinity of mAbs is the use of surface plasmon resonance (SPR) screening(such as by analysis with a BIAcore™ SPR analytical device).

Within the context herein a “determinant” designates a site ofinteraction or binding on a polypeptide.

The term “epitope” refers to an antigenic determinant, and is the areaor region on an antigen to which an antibody binds. A protein epitopemay comprise amino acid residues directly involved in the binding aswell as amino acid residues which are effectively blocked by thespecific antigen-binding antibody or peptide, i.e., amino acid residueswithin the “footprint” of the antibody. It is the simplest form orsmallest structural area on a complex antigen molecule that can combinewith, e.g., an antibody or a receptor. Epitopes can be linear orconformational/structural. The term “linear epitope” is defined as anepitope composed of amino acid residues that are contiguous on thelinear sequence of amino acids (primary structure). The term“conformational or structural epitope” is defined as an epitope composedof amino acid residues that are not all contiguous and thus representseparated parts of the linear sequence of amino acids that are broughtinto proximity to one another by folding of the molecule (secondary,tertiary and/or quaternary structures). A conformational epitope isdependent on the 3-dimensional structure. The term ‘conformational’ istherefore often used interchangeably with ‘structural’.

The term “immunogenic fragment” refers to any polypeptidic or peptidicfragment that is capable of eliciting an immune response such as (i) thegeneration of antibodies binding said fragment and/or binding any formof the molecule comprising said fragment, including the membrane-boundreceptor and mutants derived therefrom, or (ii) the stimulation of aT-cell response involving T-cells reacting to the bi-molecular complexcomprising any MHC molecule and a peptide derived from said fragment.Alternatively, an immunogenic fragment also refers to any constructioncapable of eliciting an immune response as defined above, such as apeptidic fragment conjugated to a carrier protein by covalent coupling,or a chimeric recombinant polypeptide construct comprising said peptidicfragment in its amino acid sequence, and specifically includes cellstransfected with a cDNA of which the sequence comprises a portionencoding said fragment.

The term “depleting”, “deplete” or “depletion”, with respect toNKp46-expressing cells, means a process, method, or compound that cankill, eliminate, lyse or induce such killing, elimination or lysis, soas to negatively affect the number of NKp46-expressing cells present ina sample or in a subject.

The terms “immunoconjugate”, “antibody conjugate”, “antibody drugconjugate”, and “ADC” are used interchangeably and refer to an antibodythat is conjugated to another moiety (e.g., any non-antibody moiety, atherapeutic agent or a label).

The term “agent” is used herein to denote a chemical compound, a mixtureof chemical compounds, a biological macromolecule, or an extract madefrom biological materials. The term “therapeutic agent” refers to anagent that has biological activity.

The terms “toxic agent”, “toxic moiety” and “cytotoxic agent” encompassany compound that can slow down, halt, or reverse the proliferation ofcells, decrease their activity in any detectable way, or directly orindirectly kill them. Preferably, cytotoxic agents cause cell deathprimarily by interfering directly with the cell's functioning, andinclude, but are not limited to, alkylating agents, tumor necrosisfactor inhibitors, DNA intercalators, microtubule inhibitors, kinaseinhibitors, proteasome inhibitors and topoisomerase inhibitors. A “toxicpayload” as used herein refers to a sufficient amount of cytotoxic agentwhich, when delivered to a cell, results in cell death. Delivery of atoxic payload may be accomplished by administration of a sufficientamount of immunoconjugate comprising an antibody or antigen-bindingfragment and a cytotoxic agent. Delivery of a toxic payload may also beaccomplished by administration of a sufficient amount of animmunoconjugate comprising a cytotoxic agent, wherein theimmunoconjugate comprises a secondary antibody or antigen-bindingfragment thereof which recognizes and binds an (anti-NKp46) antibody orantigen-binding fragment.

The term “human-suitable”, with respect to an antibody, refers to anyantibody, derivatized antibody, or antibody fragment that can be safelyused in humans for, e.g., the therapeutic methods described herein.Human-suitable antibodies include all types of humanized, chimeric, orfully human antibodies, or any antibodies in which at least a portion ofthe antibodies is derived from humans or otherwise modified so as toavoid the immune response that is generally provoked when nativenon-human antibodies are used.

For the purposes herein, a “humanized” or “human” antibody refers to anantibody in which the constant and variable framework region of one ormore human immunoglobulins is fused with the binding region, e.g., theCDR, of an animal immunoglobulin. Such antibodies are designed tomaintain the binding specificity of the non-human antibody from whichthe binding regions are derived, but to avoid an immune reaction againstthe non-human antibody. Such antibodies can be obtained from transgenicmice or other animals that have been “engineered” to produce specifichuman antibodies in response to antigenic challenge (see, e.g., Green etal. (1994) Nature Genet 7:13; Lonberg et al. (1994) Nature 368:856; andTaylor et al. (1994) Int Immun 6:579, the entire teachings of which areherein incorporated by reference). A fully human antibody also can beconstructed by genetic or chromosomal transfection methods, as well asphage display technology, all of which are known in the art (see, e.g.,McCafferty et al. (1990) Nature 348:552-553). Human antibodies may alsobe generated by in vitro activated B cells (see, e.g., U.S. Pat. Nos.5,567,610 and 5,229,275, which are incorporated in their entirety byreference).

A “chimeric antibody” is an antibody molecule in which (a) the constantregion, or a portion thereof, is altered, replaced or exchanged so thatthe antigen-binding site (variable region) is linked to a constantregion of a different or altered class, effector function and/orspecies, or an entirely different molecule which confers new propertiesto the chimeric antibody, e.g., an enzyme, toxin, hormone, growthfactor, drug, etc., or (b) the variable region, or a portion thereof, isaltered, replaced or exchanged with a variable region having a differentor altered antigen specificity.

The terms “Fc domain,” “Fc portion,” and “Fc region” refer to aC-terminal fragment of an antibody heavy chain, e.g., from about aminoacid (aa) 230 to about aa 450 of human γ (gamma) heavy chain or itscounterpart sequence in other types of antibody heavy chains (e.g., a,b, E and p for human antibodies), or a naturally occurring allotypethereof. Unless otherwise specified, the commonly accepted Kabat aminoacid numbering for immunoglobulins is used throughout this disclosure(see Kabat et al. (1991) Sequences of Protein of Immunological Interest,5th ed., United States Public Health Service, National Institutes ofHealth, Bethesda, Md.).

The term “antibody-dependent cell-mediated cytotoxicity” or “ADCC” is aterm well understood in the art, and refers to a cell-mediated reactionin which non-specific cytotoxic cells that express Fc receptors (FcRs)recognize bound antibody on a target cell and subsequently cause lysisof the target cell. Non-specific cytotoxic cells that mediate ADCCinclude natural killer (NK) cells, macrophages, monocytes, neutrophils,and eosinophils.

The terms “isolated”, “purified” or “biologically pure” refer tomaterial that is substantially or essentially free from components whichnormally accompany it as found in its native state. Purity andhomogeneity are typically determined using analytical chemistrytechniques such as polyacrylamide gel electrophoresis or highperformance liquid chromatography. A protein that is the predominantspecies present in a preparation is substantially purified.

The terms “polypeptide,” “peptide” and “protein” are usedinterchangeably herein to refer to a polymer of amino acid residues. Theterms apply to amino acid polymers in which one or more amino acidresidue is an artificial chemical mimetic of a corresponding naturallyoccurring amino acid, as well as to naturally occurring amino acidpolymers and non-naturally occurring amino acid polymers.

The term “recombinant”, when used with reference, e.g., to a cell,nucleic acid, protein, or vector, indicates that the cell, nucleic acid,protein or vector has been modified by the introduction of aheterologous nucleic acid or protein or the alteration of a nativenucleic acid or protein, or that the cell is derived from a cell somodified. Thus, for example, recombinant cells express genes that arenot found within the native (nonrecombinant) form of the cell or expressnative genes that are otherwise abnormally expressed, under-expressed ornot expressed at all.

As used herein, “T cells” refers to a sub-population of lymphocytes thatmature in the thymus, and which display, among other molecules, T cellreceptors on their surface. T cells can be identified by virtue ofcertain characteristics and biological properties, such as theexpression of specific surface antigens including TCR, CD4 or CD8,optionally CD4 and IL-23R, the ability of certain T cells to kill tumoror infected cells, the ability of certain T cells to activate othercells of the immune system, and the ability to release protein moleculescalled cytokines that stimulate or inhibit the immune response. Any ofthese characteristics and activities can be used to identify T cells,using methods well-known in the art.

“Prominently expressed”, when referring to an NKp46 polypeptide, meansthat the NKp46 polypeptide is expressed in a substantial number of tumorcells (e.g., PTCL cells, malignant or over-proliferating T or NK cells)taken from a given patient. While the definition of the term“prominently expressed” is not bound by a precise percentage value, inmost cases a receptor said to be “prominently expressed” will be presenton at least 30% or 40%, preferably 50%, 60%, 70%, 80%, or more, of thePTCL cells taken from a patient.

Within the context herein, the term “antibody that binds” a polypeptideor epitope designates an antibody that binds said determinant withspecificity and/or affinity.

The term “identity” or “identical”, when used in a relationship betweenthe sequences of two or more polypeptides, refers to the degree ofsequence relatedness between polypeptides, as determined by the numberof matches between strings of two or more amino acid residues.“Identity” measures the percent of identical matches between the smallerof two or more sequences with gap alignments (if any) addressed by aparticular mathematical model or computer program (i.e., “algorithms”).Identity of related polypeptides can be readily calculated by knownmethods. Such methods include, but are not limited to, those describedin Computational Molecular Biology, Lesk, A. M., ed., Oxford UniversityPress, New York, 1988; Biocomputing: Informatics and Genome Projects,Smith, D. W., ed., Academic Press, New York, 1993; Computer Analysis ofSequence Data, Part 1, Griffin, A. M., and Griffin, H. G., eds., HumanaPress, New Jersey, 1994; Sequence Analysis in Molecular Biology, vonHeinje, G., Academic Press, 1987; Sequence Analysis Primer, Gribskov, M.and Devereux, J., eds., M. Stockton Press, New York, 1991; and Carilloet al., SIAM J. Applied Math. 48, 1073 (1988).

Methods for determining identity are designed to give the largest matchbetween the sequences tested. Methods of determining identity aredescribed in publicly available computer programs. Computer programmethods for determining identity between two sequences include the GCGprogram package, including GAP (Devereux et al., Nucl. Acid. Res. 12,387 (1984); Genetics Computer Group, University of Wisconsin, Madison,Wis.), BLASTP, BLASTN, and FASTA (Altschul et al., J. Mol. Biol. 215,403-410 (1990)). The BLASTX program is publicly available from theNational Center for Biotechnology Information (NCBI) and other sources(BLAST Manual, Altschul et al., NCB/NLM/NIH, Bethesda, Md. 20894;Altschul et al., supra). The well-known Smith-Waterman algorithm mayalso be used to determine identity.

Production of Antibodies

“NKp46 polypeptide” and “NKp46 receptor” refer to a protein orpolypeptide encoded by the Ncr1 gene or by a cDNA prepared from such agene. Any naturally occurring isoform, allele or variant is encompassedby the term NKp46 polypeptide (e.g., an NKp46 polypeptide 90%, 95%, 98%or 99% identical to SEQ ID NO 1, or a contiguous sequence of at least20, 30, 50, 100 or 200 amino acid residues thereof). The 304 amino acidresidue sequence of human NKp46 (isoform a) is shown as follows:

(SEQ ID NO: 1) MSSTLPALLC VGLCLSQRIS AQQQTLPKPF IWAEPHFMVPKEKQVTICCQ GNYGAVEYQL HFEGSLFAVD RPKPPERINKVKFYIPDMNS RMAGQYSCIY RVGELWSEPS NLLDLVVTEMYDTPTLSVHP GPEVISGEKV TFYCRLDTAT SMFLLLKEGRSSHVQRGYGK VQAEFPLGPV TTAHRGTYRC FGSYNNHAWSFPSEPVKLLV TGDIENTSLA PEDPTFPADT WGTYLLTTETGLQKDHALWD HTAQNLLRMG LAFLVLVALV WFLVEDWLSR KRTRERASRA STWEGRRRLN TQTL.

SEQ ID NO: 1 corresponds to NCBI accession number NP_004820, thedisclosure of which is incorporated herein by reference. The human NKp46mRNA sequence is described in NCBI accession number NM_004829, thedisclosure of which is incorporated herein by reference.

Examples of antibodies that bind human NKp46 include, e.g., Bab281,mlgG1, available commercially from Beckman Coulter, Inc. (Brea, Calif.,USA) (see Pessino et al., J Exp Med, 1998, 188(5):953-960 and Sivori etal., Eur J Immunol, 1999, 29:1656-1666, describing chromium releasecytotoxicity assays). Another NKp46 binding antibody is 9E2, mlgG1,available commercially from Becton Dickinson (Franklin Lakes, N.J., USA)and Miltenyi Biotec (Bergisch Gladback, Germany) (see Brando et al.(2005) J Leukoc Biol 78:359-371 and EI-Sherbiny et al. (2007) CancerResearch 67(18):8444-9). Another anti-NKp46 binding antibody is 195314,mlgG2b, available commercially from R&D Systems, Inc. (Minneapolis, USA)(see Nolte-'t Hoen et al. (2007) Blood 109:670-673). These antibodiesall bind human NKp46, are of murine origin and have murine Fc domains.The antibodies all additionally inhibit the function of NKp46. Theanti-NKp46 antibodies may include antibodies having variable region orCDR sequences from such Bab281, 9E2 or 195314 antibodies (e.g., wheresuch heavy and/or light chain variable region is fused to a humanconstant region; a heavy chain variable region fused to a human IgG1heavy chain constant region); alternatively, the anti-NKp46 antibodiesmay be an antibody other than the antibodies having variable region orCDR sequences from a Bab281, 9E2 or 195314 antibody.

In one aspect, an antibody is provided that competes with monoclonalantibody BAB281, 9E2 or 195314 and recognizes, binds to, or hasimmunospecificity for substantially or essentially the same, or thesame, epitope or “epitopic site” on an NKp46 molecule as monoclonalantibody Bab281, 9E2 or 195314. In other embodiments, the monoclonalantibody consists of, or is a derivative or fragment of, antibodyBab281, 9E2 or 195314.

It will be appreciated that, while antibodies that bind to the sameepitope as antibody Bab281, 9E2 or 195314 can be used, other antibodiescan recognize and be raised against any part of the NKp46 polypeptide solong as the antibody causes the depletion of NKp46-expressing tumorcells or inhibits NKp46-expressing tumor cells' proliferation. Forexample, any fragment of NKp46, preferably but not exclusively humanNKp46, or any combination of NKp46 fragments can be used as immunogensto raise antibodies, and the antibodies can recognize epitopes at anylocation within the NKp46 polypeptide, so long as they can do so onNKp46-expressing NK cells as described herein, e.g., and lead to thedepletion of NKp46-expressing tumor cells. In an embodiment, therecognized epitopes are present on the cell surface, i.e., they areaccessible to antibodies present outside of the cell. Most preferably,the epitope is the epitope specifically recognized by antibody Bab281,9E2 or 195314. Further, antibodies recognizing distinct epitopes withinNKp46 can be used in combination, e.g., to bind to NKp46 polypeptideswith maximum efficacy and breadth among different individuals.

The antibodies may be produced by a variety of techniques known in theart. Typically, they are produced by immunization of a non-human animal,preferably a mouse, with an immunogen comprising an NKp46 polypeptide,preferably a human NKp46 polypeptide. The NKp46 polypeptide may comprisethe full length sequence of a human NKp46 polypeptide, or a fragment orderivative thereof, typically an immunogenic fragment, i.e., a portionof the polypeptide comprising an epitope exposed on the surface of cellsexpressing an NKp46 polypeptide, preferably the epitope recognized bythe Bab281, 9E2 or 195314 antibody. Such fragments typically contain atleast about 7 consecutive amino acids of the mature polypeptidesequence, even more preferably at least about 10 consecutive amino acidsthereof. Fragments typically are essentially derived from theextra-cellular domain of the receptor. In one embodiment, the immunogencomprises a wild-type human NKp46 polypeptide in a lipid membrane,typically at the surface of a cell. In a specific embodiment, theimmunogen comprises intact cells, particularly intact human cells,optionally treated or lysed. In another embodiment, the polypeptide is arecombinant NKp46 polypeptide.

The step of immunizing a non-human mammal with an antigen may be carriedout in any manner well-known in the art for stimulating the productionof antibodies in a mouse (see, for example, E. Harlow and D. Lane,Antibodies: A Laboratory Manual., Cold Spring Harbor Laboratory Press,Cold Spring Harbor, N.Y. (1988), the entire disclosure of which isherein incorporated by reference). The immunogen is suspended ordissolved in a buffer, optionally with an adjuvant, such as complete orincomplete Freund's adjuvant. Methods for determining the amount ofimmunogen, types of buffers and amounts of adjuvant are well-known tothose of skill in the art and are not limiting in any way. Theseparameters may be different for different immunogens, but are easilyelucidated.

Similarly, the location and frequency of immunization sufficient tostimulate the production of antibodies is also well-known in the art. Ina typical immunization protocol, the non-human animals are injectedintraperitoneally with antigen on day 1 and again about a week later.This is followed by recall injections of the antigen around day 20,optionally with an adjuvant such as incomplete Freund's adjuvant. Therecall injections are performed intravenously and may be repeated forseveral consecutive days. This is followed by a booster injection at day40, either intravenously or intraperitoneally, typically withoutadjuvant. This protocol results in the production of antigen-specificantibody-producing B cells after about 40 days. Other protocols may alsobe used as long as they result in the production of B cells expressingan antibody directed to the antigen used in immunization.

For polyclonal antibody preparation, serum is obtained from an immunizednon-human animal and the antibodies present therein isolated bywell-known techniques. The serum may be affinity purified using any ofthe immunogens set forth above linked to a solid support so as to obtainantibodies that react with NKp46 polypeptides.

In an alternate embodiment, lymphocytes from a non-immunized non-humanmammal are isolated, grown in vitro, and then exposed to the immunogenin cell culture. The lymphocytes are then harvested and the fusion stepdescribed below is carried out.

For monoclonal antibodies, the next step is the isolation of splenocytesfrom the immunized non-human mammal and the subsequent fusion of thosesplenocytes with an immortalized cell in order to form anantibody-producing hybridoma. The isolation of splenocytes from anon-human mammal is well-known in the art and typically involvesremoving the spleen from an anesthetized non-human mammal, cutting itinto small pieces and squeezing the splenocytes from the splenic capsulethrough a nylon mesh of a cell strainer into an appropriate buffer so asto produce a single cell suspension. The cells are washed, centrifugedand resuspended in a buffer that lyses any red blood cells. The solutionis again centrifuged and remaining lymphocytes in the pellet are finallyresuspended in fresh buffer.

Once isolated and present in single cell suspension, the lymphocytes canbe fused to an immortal cell line. This is typically a mouse myelomacell line, although many other immortal cell lines useful for creatinghybridomas are known in the art. Murine myeloma lines include, but arenot limited to, those derived from MOPC-21 and MPC-11 mouse tumorsavailable from the Salk Institute Cell Distribution Center, San Diego,U.S.A. and X63 Ag8653 and SP-2 cells available from the American TypeCulture Collection, Rockville, Md. U.S.A. The fusion is effected usingpolyethylene glycol or the like. The resulting hybridomas are then grownin selective media that contains one or more substances that inhibit thegrowth or survival of the unfused, parental myeloma cells. For example,if the parental myeloma cells lack the enzyme hypoxanthine guaninephosphoribosyl transferase (HGPRT or HPRT), the culture medium for thehybridomas typically will include hypoxanthine, aminopterin, andthymidine (HAT medium), which substances prevent the growth ofHGPRT-deficient cells.

Hybridomas are typically grown on a feeder layer of macrophages. Themacrophages are preferably from littermates of the non-human mammal usedto isolate splenocytes and are typically primed with incomplete Freund'sadjuvant or the like several days before plating the hybridomas. Fusionmethods are described in Goding, Monoclonal Antibodies: Principles andPractice, pp. 59-103 (Academic Press, 1986), the disclosure of which isherein incorporated by reference.

The cells are allowed to grow in the selection media for sufficient timefor colony formation and antibody production. This is usually betweenabout 7 and about 14 days.

The hybridoma colonies are then assayed for the production of antibodiesthat specifically bind to NKp46 polypeptide gene products, optionallythe epitope specifically recognized by antibody Bab281, 9E2 or 195314.The assay is typically a colorimetric ELISA-type assay, although anyassay may be employed that can be adapted to the wells that thehybridomas are grown in. Other assays include radioimmunoassays orfluorescence-activated cell sorting. The wells positive for the desiredantibody production are examined to determine if one or more distinctcolonies are present. If more than one colony is present, the cells maybe re-cloned and grown to ensure that only a single cell has given riseto the colony producing the desired antibody. Typically, the antibodieswill also be tested for the ability to bind to NKp46 polypeptides, e.g.,NKp46-expressing cells.

Hybridomas that are confirmed to produce a monoclonal antibody can begrown in larger amounts in an appropriate medium, such as DMEM orRPMI-1640. Alternatively, the hybridoma cells can be grown in vivo asascites tumors in an animal.

After sufficient growth to produce the desired monoclonal antibody, thegrowth media containing monoclonal antibody (or the ascites fluid) isseparated away from the cells and the monoclonal antibody presenttherein is purified. Purification is typically achieved by gelelectrophoresis, dialysis, chromatography using protein A or protein GSepharose, or an anti-mouse Ig linked to a solid support such as agaroseor Sepharose beads (all described, for example, in the AntibodyPurification Handbook, Biosciences, Publication No. 18-1037-46, EditionAC, the disclosure of which is hereby incorporated by reference). Thebound antibody is typically eluted from protein A/protein G columns byusing low pH buffers (glycine or acetate buffers of pH 3.0 or less) withimmediate neutralization of antibody-containing fractions. Thesefractions are pooled, dialyzed, and concentrated as needed.

Positive wells with a single apparent colony are typically re-cloned andre-assayed to insure only one monoclonal antibody is being detected andproduced.

Antibodies may also be produced by selection of combinatorial librariesof immunoglobulins, as disclosed for instance in Ward et al., Nature,341 (1989), p. 544, the entire disclosure of which is hereinincorporated by reference.

The identification of one or more antibodies that bind(s) to NKp46,particularly substantially or essentially the same epitope as monoclonalantibody Bab281, 9E2 or 195314, can be readily determined using any oneof a variety of immunological screening assays in which antibodycompetition can be assessed. Many such assays are routinely practicedand are well-known in the art (see, e.g., U.S. Pat. No. 5,660,827,issued Aug. 26, 1997, which is specifically incorporated herein byreference). It will be understood that actually determining the epitopeto which an antibody described herein binds is not in any way requiredto identify an antibody that binds to the same or substantially the sameepitope as the monoclonal antibody described herein.

For example, where the test antibodies to be examined are obtained fromdifferent source animals, or are even of a different Ig isotype, asimple competition assay may be employed in which the control (Bab281,9E2 or 195314, for example) and test antibodies are admixed (orpre-adsorbed) and applied to a sample containing NKp46 polypeptides.Protocols based upon Western blotting and the use of BIACORE analysisare suitable for use in such competition studies.

In certain embodiments, one pre-mixes the control antibodies (Bab281,9E2 or 195314, for example) with varying amounts of the test antibodies(e.g., about 1:10 or about 1:100) for a period of time prior to applyingto the NKp46 antigen sample. In other embodiments, the control andvarying amounts of test antibodies can simply be admixed during exposureto the NKp46 antigen sample. As long as one can distinguish bound fromfree antibodies (e.g., by using separation or washing techniques toeliminate unbound antibodies) and Bab281, 9E2 or 195314 from the testantibodies (e.g., by using species-specific or isotype-specificsecondary antibodies or by specifically labeling Bab281, 9E2 or 195314with a detectable label), one can determine if the test antibodiesreduce the binding of Bab281, 9E2 or 195314 to the antigens, indicatingthat the test antibody recognizes substantially the same epitope asBab281, 9E2 or 195314. The binding of the (labeled) control antibodiesin the absence of a completely irrelevant antibody can serve as thecontrol high value. The control low value can be obtained by incubatingthe labeled (Bab281, 9E2 or 195314) antibodies with unlabeled antibodiesof exactly the same type (Bab281, 9E2 or 195314), where competitionwould occur and reduce binding of the labeled antibodies. In a testassay, a significant reduction in labeled antibody reactivity in thepresence of a test antibody is indicative of a test antibody thatrecognizes substantially the same epitope, i.e., one that “cross-reacts”or competes with the labeled (Bab281, 9E2 or 195314) antibody. Any testantibody that reduces the binding of Bab281, 9E2 or 195314 to NKp46antigens by at least about 50%, such as at least about 60%, or morepreferably at least about 80% or 90% (e.g., about 65-100%), at any ratioof Bab281, 9E2 or 195314:test antibody between about 1:10 and about1:100 is considered to be an antibody that binds to substantially thesame epitope or determinant as Bab281, 9E2 or 195314. Preferably, suchtest antibody will reduce the binding of Bab281, 9E2 or 195314 to theNKp46 antigen by at least about 90% (e.g., about 95%).

Competition can also be assessed by, for example, a flow cytometry test.In such a test, cells bearing a given NKp46 polypeptide can be incubatedfirst with Bab281, 9E2 or 195314, for example, and then with the testantibody labeled with a fluorochrome or biotin. The antibody is said tocompete with Bab281, 9E2 or 195314 if the binding obtained uponpreincubation with a saturating amount of Bab281, 9E2 or 195314 is about80%, preferably about 50%, about 40% or less (e.g., about 30%, 20% or10%) of the binding (as measured by mean of fluorescence) obtained bythe antibody without pre-incubation with Bab281, 9E2 or 195314.Alternatively, an antibody is said to compete with Bab281, 9E2 or 195314if the binding obtained with a labeled Bab281, 9E2 or 195314 antibody(by a fluorochrome or biotin) on cells preincubated with a saturatingamount of test antibody is about 80%, preferably about 50%, about 40%,or less (e.g., about 30%, 20% or 10%) of the binding obtained withoutpreincubation with the test antibody.

A simple competition assay in which a test antibody is pre-adsorbed andapplied at saturating concentration to a surface onto which an NKp46antigen is immobilized may also be employed. The surface in the simplecompetition assay is preferably a Biacore chip (or other media suitablefor surface plasmon resonance analysis). The control antibody (e.g.,Bab281, 9E2 or 195314) is then brought into contact with the surface atan NKp46-saturating concentration and the NKp46 and surface binding ofthe control antibody is measured. This binding of the control antibodyis compared with the binding of the control antibody to theNKp46-containing surface in the absence of test antibody. In a testassay, a significant reduction in binding of the NKp46-containingsurface by the control antibody in the presence of a test antibodyindicates that the test antibody recognizes substantially the sameepitope as the control antibody, such that the test antibody“cross-reacts” with the control antibody. Any test antibody that reducesthe binding of control (such as Bab281, 9E2 or 195314) antibody to anNKp46 antigen by at least about 30% or more, preferably about 40%, canbe considered to be an antibody that binds to substantially the sameepitope or determinant as a control (e.g., Bab281, 9E2 or 195314).Preferably, such a test antibody will reduce the binding of the controlantibody (e.g., Bab281, 9E2 or 195314) to the NKp46 antigen by at leastabout 50% (e.g., at least about 60%, at least about 70%, or more). Itwill be appreciated that the order of control and test antibodies can bereversed: that is, the control antibody can be first bound to thesurface and the test antibody is brought into contact with the surfacethereafter in a competition assay. Preferably, the antibody havinghigher affinity for the NKp46 antigen is bound to the surface first, asit will be expected that the decrease in binding seen for the secondantibody (assuming the antibodies are cross-reacting) will be of greatermagnitude. Further examples of such assays are provided in, e.g., Saunal(1995) J. Immunol. Methods 183: 33-41, the disclosure of which isincorporated herein by reference.

Determination of whether an antibody binds within an epitope region canbe carried out in ways known to the person skilled in the art. As oneexample of such mapping/characterization methods, an epitope region foran anti-NKp46 antibody may be determined by epitope “foot-printing”using chemical modification of the exposed amines/carboxyls in the NKp46protein. One specific example of such a foot-printing technique is theuse of HXMS (hydrogen-deuterium exchange detected by mass spectrometry)wherein a hydrogen/deuterium exchange of receptor and ligand proteinamide protons, binding, and back exchange occurs, wherein the backboneamide groups participating in protein binding are protected from backexchange and therefore will remain deuterated. Relevant regions can beidentified at this point by peptic proteolysis, fast microborehigh-performance liquid chromatography separation, and/or electrosprayionization mass spectrometry. See, e.g., Ehring, H., AnalyticalBiochemistry, 267(2):252-259 (1999) and Engen, J. R. and Smith, D. L.Anal. Chem. 73:256A-265A (2001). Another example of a suitable epitopeidentification technique is nuclear magnetic resonance epitope mapping(NMR), where typically the position of the signals in two-dimensionalNMR spectra of the free antigen and the antigen complexed with theantigen-binding peptide, such as an antibody, are compared. The antigentypically is selectively isotopically labeled with 15N so that onlysignals corresponding to the antigen and no signals from theantigen-binding peptide are seen in the NMR spectrum. Antigen signalsoriginating from amino acids involved in the interaction with theantigen-binding peptide typically will shift position in the spectrum ofthe complex compared to the spectrum of the free antigen, and the aminoacids involved in the binding can be identified that way. See, e.g.,Ernst Schering Res Found Workshop, 2004, (44):149-67; Huang et al.,Journal of Molecular Biology, 281(1):61-67 (1998); and Saito andPatterson, Methods, 1996 Jun., 9(3):516-24.

Epitope mapping/characterization also can be performed using massspectrometry methods. See, e.g., Downard, J. Mass. Spectrom., 2000April, 35(4):493-503 and Kiselar and Downard, Anal. Chem., 1999 May 1,71(9):1792-801. Protease digestion techniques also can be useful in thecontext of epitope mapping and identification. Antigenicdeterminant-relevant regions/sequences can be determined by proteasedigestion, e.g., by using trypsin in a ratio of about 1:50 to NKp46 orovernight digestion at pH 7-8, followed by mass spectrometry (MS)analysis for peptide identification. The peptides protected from trypsincleavage by the anti-NKp46 binder can subsequently be identified bycomparison of samples subjected to trypsin digestion and samplesincubated with antibody and then subjected to digestion by, e.g.,trypsin (thereby revealing a footprint for the binder). Other enzymeslike chymotrypsin, pepsin, etc. also or alternatively can be used insimilar epitope characterization methods. Moreover, enzymatic digestioncan provide a quick method for analyzing whether a potential antigenicdeterminant sequence is within a region of the NKp46 polypeptide that isnot surface exposed and, accordingly, most likely not relevant in termsof immunogenicity/antigenicity. See, e.g., Manca, Ann Ist Super Sanita,1991, 27:15-9 for a discussion of similar techniques.

Site-directed mutagenesis is another technique useful for elucidation ofa binding epitope. For example, in “alanine scanning”, each residuewithin a protein segment is replaced with an alanine residue, and theconsequences for binding affinity measured. If the mutation leads to asignificant reduction in binding affinity, it is most likely involved inbinding. Monoclonal antibodies specific for structural epitopes (i.e.,antibodies which do not bind the unfolded protein) can be used to verifythat the alanine-replacement does not influence the overall fold of theprotein. See, e.g., Clackson and Wells, Science, 1995, 267:383-386 andWells, Proc Natl Acad Sci USA, 1996, 93:1-6.

Electron microscopy can also be used for epitope “foot-printing”. Forexample, Wang et al., Nature 1992; 355:275-278 used coordinatedapplication of cryoelectron microscopy, three-dimensional imagereconstruction, and X-ray crystallography to determine the physicalfootprint of a Fab-fragment on the capsid surface of native cowpeamosaic virus.

Other forms of “label-free” assay for epitope evaluation include surfaceplasmon resonance (SPR, Biacore) and reflectometric interferencespectroscopy (RIfS). See, e.g., Fagerstam et al., Journal of MolecularRecognition, 1990, 3:208-14; Nice et al., J. Chromatogr., 1993,646:159-168; Leipert et al., Angew. Chem. Int. Ed., 1998, 37:3308-3311;and Kroger et al., Biosensors and Bioelectronics, 2002, 17:937-944.

It should also be noted that an antibody binding the same orsubstantially the same epitope as an antibody can be identified in oneor more of the exemplary competition assays described herein.

Once antibodies are identified that are capable of binding NKp46 and/orhaving other desired properties, they will also typically be assessed,using standard methods including those described herein, for theirability to bind to other polypeptides, including unrelated polypeptides.Ideally, the antibodies only bind with substantial affinity to NKp46,e.g., human NKp46, and do not bind at a significant level to unrelatedpolypeptides. However, it will be appreciated that, as long as theaffinity for NKp46 is substantially greater (e.g., 5×, 10×, 50×, 100×,500×, 1000×, 10,000×, or more) than it is for other, unrelatedpolypeptides), then the antibodies are suitable for use in the presentmethods.

The binding of the antibodies to NKp46-expressing cells can also beassessed in non-human primates, e.g., cynomolgus monkeys, or othermammals such as mice. The disclosure therefore provides an antibody, aswell as fragments and derivatives thereof, wherein said antibody,fragment or derivative specifically binds NKp46, and which furthermorebinds NKp46 from non-human primates, e.g., cynomolgus monkeys.

Upon immunization and production of antibodies in a vertebrate or cell,particular selection steps may be performed to isolate antibodies asclaimed. In this regard, the disclosure also relates to methods ofproducing such antibodies, comprising: (a) immunizing a non-human mammalwith an immunogen comprising an NKp46 polypeptide; (b) preparingantibodies from said immunized animal; and (c) selecting antibodies fromstep (b) that are capable of binding NKp46.

In one aspect of any of the embodiments, the antibodies preparedaccording to the present methods are monoclonal antibodies. In anotheraspect, the non-human animal used to produce antibodies according to themethods herein is a mammal, such as a rodent, bovine, porcine, fowl,horse, rabbit, goat, or sheep.

According to an alternate embodiment, the DNA encoding an antibody thatbinds an epitope present on NKp46 polypeptides is isolated from thehybridoma and placed in an appropriate expression vector fortransfection into an appropriate host. The host is then used for therecombinant production of the antibody, or variants thereof, such as ahumanized version of that monoclonal antibody, active fragments of theantibody, chimeric antibodies comprising the antigen recognition portionof the antibody, or versions comprising a detectable moiety.

DNA encoding the monoclonal antibodies, e.g., antibody Bab281, 9E2 or195314, can be readily isolated and sequenced using conventionalprocedures (e.g., by using oligonucleotide probes that are capable ofbinding specifically to genes encoding the heavy and light chains ofmurine antibodies). Once isolated, the DNA can be placed into expressionvectors, which are then transfected into host cells such as E. colicells, simian COS cells, Chinese hamster ovary (CHO) cells, or myelomacells that do not otherwise produce immunoglobulin protein, to obtainthe synthesis of monoclonal antibodies in the recombinant host cells. Asdescribed elsewhere in the present specification, such DNA sequences canbe modified for any of a large number of purposes, e.g., for humanizingantibodies, producing fragments or derivatives, or modifying thesequence of the antibody, e.g., in the antigen-binding site in order tooptimize the binding specificity of the antibody.

Recombinant expression in bacteria of DNA encoding the antibody iswell-known in the art (see, for example, Skerra et al., Curr. Opinion inImmunol., 5:256 (1993) and Pluckthun, Immunol. 130:151 (1992).

Once an antigen-binding compound is obtained it may be assessed for itsability to induce ADCC or CDC towards, inhibit the activity and/orproliferation of and/or cause the elimination of NKp46-expressing targetcells. Assessing the antigen-binding compound's ability to induce ADCCor CDC (complement-dependent cytotoxicity) or generally lead to theelimination or inhibition of activity of NKp46-expressing target cellscan be carried out at any suitable stage of the method. This assessmentcan be useful at one or more of the various steps involved in theidentification, production and/or development of an antibody (or othercompound) destined for therapeutic use. For example, activity may beassessed in the context of a screening method to identify candidateantigen-binding compounds, or in methods where an antigen-bindingcompound is selected and made human-suitable (e.g., made chimeric orhumanized in the case of an antibody), where a cell expressing theantigen-binding compound (e.g., a host cell expressing a recombinantantigen-binding compound) has been obtained and is assessed for itsability to produce functional antibodies (or other compounds), and/orwhere a quantity of antigen-binding compound has been produced and is tobe assessed for activity (e.g., to test batches or lots of product).Generally the antigen-binding compound will be known to specificallybind to an NKp46 polypeptide. The step may involve testing a plurality(e.g., a very large number using high-throughput screening methods or asmaller number) of antigen-binding compounds.

Testing CDC and ADCC can be carried out can be determined by variousassays including those known in the art and those described in theexperimental examples herein. Testing ADCC typically involves assessingcell-mediated cytotoxicity in which an NKp46-expressing target cell(e.g., a PTCL cell or other NKp46-expressing cell) with bound anti-NKp46antibody is recognized by an effector cell bearing Fc receptors, withoutthe involvement of complement. A cell which does not express an NKp46antigen can optionally be used as a control. Activation of NK cellcytotoxicity is assessed by measuring an increase in cytokine production(e.g., IFN-γ production) or cytotoxicity markers (e.g., CD107mobilization). Preferably the antibody will induce an increase incytokine production, expression of cytoxicity markers, or target celllysis of at least 20%, 50%, 80%, 100%, 200% or 500% in the presence oftarget cells, compared to a control antibody (e.g., an antibody notbinding to NKp46, an NKp46 antibody having murine constant regions). Inanother example, lysis of target cells is detected, e.g., in a chromiumrelease assay; preferably the antibody will induce lysis of at least10%, 20%, 30%, 40% or 50% of target cells.

Fragments and derivatives of antibodies (which are encompassed by theterm “antibody” or “antibodies” as used in this application, unlessotherwise stated or clearly contradicted by context) can be produced bytechniques that are known in the art. “Fragments” comprise a portion ofthe intact antibody, generally the antigen-binding site or variableregion. Examples of antibody fragments include Fab, Fab′, Fab′-SH,F(ab′)2, and Fv fragments; diabodies; any antibody fragment that is apolypeptide having a primary structure consisting of one uninterruptedsequence of contiguous amino acid residues (referred to herein as a“single-chain antibody fragment” or “single chain polypeptide”),including without limitation (1) single-chain Fv molecules, (2) singlechain polypeptides containing only one light chain variable domain, or afragment thereof that contains the three CDRs of the light chainvariable domain, without an associated heavy chain moiety and (3) singlechain polypeptides containing only one heavy chain variable region, or afragment thereof containing the three CDRs of the heavy chain variableregion, without an associated light chain moiety; and multispecificantibodies formed from antibody fragments. Included, inter alia, are ananobody, domain antibody, single domain antibody or “dAb”.

In certain embodiments, the DNA of a hybridoma producing an antibody canbe modified prior to insertion into an expression vector, for example,by substituting the coding sequence for human heavy- and light-chainconstant domains in place of the homologous non-human sequences (e.g.,Morrison et al., PNAS, p. 6851 (1984)), or by covalently joining to theimmunoglobulin coding sequence all or part of the coding sequence for anon-immunoglobulin polypeptide. In that manner, “chimeric” or “hybrid”antibodies are prepared that have the binding specificity of theoriginal antibody. Typically, such non-immunoglobulin polypeptides aresubstituted for the constant domains of an antibody.

Thus, according to another embodiment, the antibody is humanized.“Humanized” forms of antibodies are specific chimeric immunoglobulins,immunoglobulin chains or fragments thereof (such as Fv, Fab, Fab′,F(ab′)2, or other antigen-binding subsequences of antibodies) whichcontain a minimal sequence derived from the murine immunoglobulin. Forthe most part, humanized antibodies are human immunoglobulins (recipientantibody) in which residues from a complementarity-determining region(CDR) of the recipient are replaced by residues from a CDR of theoriginal antibody (donor antibody) while maintaining the desiredspecificity, affinity, and capacity of the original antibody.

In some instances, Fv framework residues of the human immunoglobulin maybe replaced by corresponding non-human residues. Furthermore, humanizedantibodies can comprise residues that are not found in either therecipient antibody or in the imported CDR or framework sequences. Thesemodifications are made to further refine and optimize antibodyperformance. In general, the humanized antibody will comprisesubstantially all of at least one, and typically two, variable domains,in which all or substantially all of the CDR regions correspond to thoseof the original antibody and all or substantially all of the FR regionsare those of a human immunoglobulin consensus sequence. The humanizedantibody optimally also will comprise at least a portion of animmunoglobulin constant region (Fc), typically that of a humanimmunoglobulin. For further details see Jones et al., Nature, 321: p.522 (1986); Reichmann et al., Nature, 332: p. 323 (1988); Presta, Curr.Op. Struct. Biol., 2: p. 593 (1992); Verhoeyen et al., Science, 239: p.1534; and U.S. Pat. No. 4,816,567, the entire disclosures of which areherein incorporated by reference.) Methods for humanizing the antibodiesare well-known in the art.

The choice of human variable domains, both light and heavy, to be usedin making the humanized antibodies is very important to reduceantigenicity. According to the so-called “best-fit” method, the sequenceof the variable domain of an antibody is screened against the entirelibrary of known human variable-domain sequences. The human sequencewhich is closest to that of the mouse is then accepted as the humanframework (FR) for the humanized antibody (Sims et al., J. Immunol.,151: p. 2296 (1993); Chothia and Lesk, J. Mol. Biol., 196: p. 901(1987)). Another method uses a particular framework from the consensussequence of all human antibodies of a particular subgroup of light orheavy chains. The same framework can be used for several differenthumanized antibodies (Carter et al., PNAS, 89: p. 4285 (1992); Presta etal., J. Immunol., 151: p. 2623 (1993)).

It is further important that antibodies be humanized with retention ofhigh affinity for NKp46 receptors and other favorable biologicalproperties. To achieve this goal, according to one method, humanizedantibodies are prepared by a process of analysis of the parentalsequences and various conceptual humanized products usingthree-dimensional models of the parental and humanized sequences.Three-dimensional immunoglobulin models are commonly available and arefamiliar to those skilled in the art. Computer programs are availablewhich illustrate and display probable three-dimensional structures ofselected candidate immunoglobulin sequences. Inspection of thesedisplays permits analysis of the likely role of the residues in thefunctioning of the candidate immunoglobulin sequence, i.e., the analysisof residues that influence the ability of the candidate immunoglobulinto bind its antigen. In this way, FR residues can be selected andcombined from the consensus and import sequences so that the desiredantibody characteristic, such as increased affinity for the targetantigen(s), is achieved. In general, the CDR residues are directly andmost substantially involved in influencing antigen binding.

Another method of making “humanized” monoclonal antibodies is to use aXenoMouse (Abgenix, Fremont, Calif.) as the mouse used for immunization.A XenoMouse is a murine host that has had its immunoglobulin genesreplaced by functional human immunoglobulin genes. Thus, antibodiesproduced by this mouse or in hybridomas made from the B cells of thismouse are already humanized. The XenoMouse is described in U.S. Pat. No.6,162,963, which is herein incorporated in its entirety by reference.

Human antibodies may also be produced according to various othertechniques, such as by using, for immunization, other transgenic animalsthat have been engineered to express a human antibody repertoire(Jakobovitz et al., Nature 362:255 (1993)), or by selection of antibodyrepertoires using phage display methods. Such techniques are known tothe skilled person and can be implemented starting from monoclonalantibodies as disclosed in the present application.

In one embodiment, an NKp46 binding compound is provided, preferably ananti-NKp46 antibody, further bound to a second moiety, wherein theantibody is capable of delivering the second moiety to anNKp46-expressing cell. Optionally the second moiety is a therapeuticagent or a toxic agent (e.g., in the treatment methods where the NKp46binding compound is intended for administration to an individual),and/or a detectable agent (e.g., when the NKp46 binding compound isintended for use in a detection step).

While antibodies in underivatized or unmodified form, particularly ofthe IgG1 or IgG3 type, can be cytotoxic towards overproliferating cellssuch as those from a PTCL patient, e.g., by directing ADCC and/or CDCtoward NKp46-expressing PTCL cells, it is also possible to preparederivatized antibody immunoconjugates that are cytotoxic. In oneembodiment, once the NKp46-specific antibodies are isolated andoptionally otherwise modified (e.g., humanized), they will bederivatized to make them toxic to cells. In this way, administration ofthe antibody to PTCL patients will lead to the relatively specificbinding of the antibody to overproliferating cells, thereby directlykilling or inhibiting the cells underlying the disorder.

Any of a large number of toxic moieties or strategies can be used toproduce such antibodies. In certain embodiments, the antibodies will bedirectly derivatized with radioisotopes or other toxic compounds.Examples of toxic agents used in immunoconjugates in developmentinclude, in particular, taxanes, anthracyclines, camptothecins,epothilones, mytomycins, combretastatins, vinca alkaloids, nitrogenmustards, maytansinoids, calicheamycins, duocarmycins, tubulysins,dolastatins and auristatins, enediynes, pyrrolobenzodiazepines,ethylenimines, radioisotopes, therapeutic proteins and peptides, andtoxins or fragments thereof. Any type of moiety with a cytotoxic orcytoinhibitory effect can be used in conjunction with the presentantibodies to inhibit or kill specific NK receptor-expressing cells,including radioisotopes, toxic proteins, and toxic small molecules, suchas drugs, toxins, immunomodulators, hormones, hormone antagonists,enzymes, oligonucleotides, enzyme inhibitors, therapeutic radionuclides,angiogenesis inhibitors, chemotherapeutic drugs, vinca alkaloids,epidophyllotoxins, antimetabolites, alkylating agents, antibiotics,antimitotics, and antiangiogenic and apoptotoic agents, particularlydoxorubicin, methotrexate, camptothecans, nitrogen mustards,gemcitabine, alkyl sulfonates, nitrosoureas, triazenes, folic acidanalogs, pyrimidine analogs, purine analogs, platinum coordinationcomplexes, Pseudomonas exotoxin, ricin, 5-fluorouridine, ribonuclease(RNase), DNase I, Staphylococcal enterotoxin-A, pokeweed antiviralprotein, gelonin, diphtherin toxin, Pseudomonas exotoxin, Pseudomonasendotoxin and others (see, e.g., Remington's Pharmaceutical Sciences,19th Ed. (Mack Publishing Co. 1995); Goodman and Gilman's ThePharmacological Basis of Therapeutics (McGraw-Hill, 2001); Pastan et al.(1986) Cell 47:641; Goldenberg (1994) Cancer Journal for Clinicians44:43; and U.S. Pat. No. 6,077,499, the entire disclosures of which areherein incorporated by reference).

In one embodiment, the antibody will be derivatized with a radioactiveisotope. Any of a number of suitable radioactive isotopes can be used,including, but not limited to, Indium-111, Lutetium-171, Bismuth-212,Bismuth-213, Astatine-211, Copper-62, Copper-64, Copper-67, Yttrium-90,Iodine-125, Iodine-131, Phosphorus-32, Phosphorus-33, Scandium-47,Silver-ill, Gallium-67, Praseodymium-142, Samarium-153, Terbium-161,Dysprosium-166, Holmium-166, Rhenium-186, Rhenium-188, Rhenium-189,Lead-212, Radium-223, Actinium-225, Iron-59, Selenium-75, Arsenic-77,Strontium-89, Molybdenum-99, Rhodium-105, Palladium-109,Praseodymium-143, Promethium-149, Erbium-169, Iridium-194, Gold-198,Gold-199, and Lead-211. In general, the radionuclide preferably has adecay energy in the range of 20 to 6,000 keV, preferably in the rangesof 60 to 200 keV for an Auger emitter, 100-2,500 keV for a beta emitter,and 4,000-6,000 keV for an alpha emitter. Also envisaged areradionuclides that substantially decay with generation ofalpha-particles.

In view of the ability of the anti-NKp46 antibodies to induce ADCC andCDC, the antibodies can also be made with modifications that increasetheir ability to bind Fc receptors which can affect effector functionssuch as antibody-dependent cytotoxicity, mast cell degranulation, andphagocytosis, as well as immunomodulatory signals such as regulation oflymphocyte proliferation and antibody secretion. Typical modificationsinclude modified human IgG1 constant regions comprising at least oneamino acid modification (e.g., substitutions, deletions, insertions),and/or altered types of glycosylation, e.g., hypofucosylation. Suchmodifications can affect interaction with Fc receptors: FcγRI (CD64),FcγRII (CD32), and FcγRII (CD 16). FcγRI (CD64), FcγRIIA (CD32A) andFcγRII (CD 16) are activating (i.e., immune system-enhancing) receptorswhile FcγRIIB (CD32B) is an inhibiting (i.e., immune system-dampening)receptor. A modification may, for example, increase binding of the Fcdomain to FcγRIIa on effector (e.g., NK) cells.

Anti-NKp46 antibodies preferably comprise an Fc domain (or portionthereof) of human IgG1 or IgG3 isotype, optionally modified. Residues230-341 (Kabat EU) are the Fc CH2 region. Residues 342-447 (Kabat EU)are the Fc CH3 region. Anti-NKp46 antibodies may comprise a variant Fcregion having one or more amino acid modifications (e.g., substitutions,deletions, insertions) in one or more portions, which modificationsincrease the affinity and avidity of the variant Fc region for an FcγR(including activating and inhibitory FcγRs). In some embodiments, saidone or more amino acid modifications increase the affinity of thevariant Fc region for FcγRIIIA and/or FcγRIIA. In another embodiment,the variant Fc region further specifically binds FcγRIIB with a loweraffinity than does the Fc region of the comparable parent antibody(i.e., an antibody having the same amino acid sequence as the antibodyexcept for the one or more amino acid modifications in the Fc region).For example, one or both of the histidine residues at amino acidpositions 310 and 435 may be substituted, for example by lysine,alanine, glycine, valine, leucine, isoleucine, proline, methionine,tryptophan, phenylalanine, serine or threonine (see, e.g., PCTPublication No. WO 2007/080277); such substituted constant regionsprovide decreased binding to the inhibitory FcγRIIB without decreasingbinding to the activatory FcγRIIIA. In some embodiments, suchmodifications increase the affinity of the variant Fc region forFcγRIIIA and/or FcγRIIA and also enhance the affinity of the variant Fcregion for FcγRIIB relative to the parent antibody. In otherembodiments, said one or more amino acid modifications increase theaffinity of the variant Fc region for FcγRIIIA and/or FcγRIIA but do notalter the affinity of the variant Fc regions for FcγRIIB relative to theFc region of the parent antibody. In another embodiment, said one ormore amino acid modifications enhance the affinity of the variant Fcregion for FcγRIIIA and FcγRIIA but reduce the affinity for FcγRIIBrelative to the parent antibody. Increased affinity and/or avidityresults in detectable binding to the FcγR or FcγR-related activity incells that express low levels of the FcγR when binding activity of theparent molecule (without the modified Fc region) cannot be detected inthe cells.

The affinities and binding properties of the anti-NKp46 antibodies foran FcγR can be determined using in vitro assays (biochemical orimmunological based assays) known in the art for determiningantibody-antigen or Fc-FcγR interactions, i.e., specific binding of anantigen to an antibody or specific binding of an Fc region to an FcγR,respectively, including but not limited to ELISA assay, surface plasmonresonance assay, and immunoprecipitation assays.

In some embodiments, anti-NKp46 antibodies comprising a variant Fcregion comprise at least one amino acid modification (for example,possessing 1, 2, 3, 4, 5, 6, 7, 8, 9, or more amino acid modifications)in the CH3 domain of the Fc region. In other embodiments, anti-NKp46antibodies comprising a variant Fc region comprise at least one aminoacid modification (for example, possessing 1, 2, 3, 4, 5, 6, 7, 8, 9, ormore amino acid modifications) in the CH2 domain of the Fc region, whichis defined as extending from amino acids 231-341. In some embodiments,anti-NKp46 antibodies comprise at least two amino acid modifications(for example, possessing 2, 3, 4, 5, 6, 7, 8, 9, or more amino acidmodifications), wherein at least one such modification is in the CH3region and at least one such modification is in the CH2 region. Furtherencompassed are amino acid modifications in the hinge region. In aparticular embodiment, amino acid modifications in the CH1 domain of theFc region, which is defined as extending from amino acids 216-230, areencompassed.

Any combination of Fc modifications can be made, for example anycombination of different modifications disclosed in U.S. Pat. Nos.7,632,497; 7,521,542; 7,425,619; 7,416,727; 7,371,826; 7,355,008;7,335,742; 7,332,581; 7,183,387; 7,122,637; 6,821,505 and 6,737,056; inPCT Publications Nos. WO2011/109400; WO 2008/105886; WO 2008/002933; WO2007/021841; WO 2007/106707; WO 06/088494; WO 05/115452; WO 05/110474;WO 04/1032269; WO 00/42072; WO 06/088494; WO 07/024249; WO 05/047327; WO04/099249 and WO 04/063351; and in Presta, L. G. et al. (2002) Biochem.Soc. Trans. 30(4):487-490; Shields, R. L. et al. (2002) J. Biol. Chem.26; 277(30):26733-26740 and Shields, R. L. et al. (2001) J. Biol. Chem.276(9):6591-6604.

Anti-NKp46 antibodies may comprise a variant Fc region, wherein thevariant Fc region comprises at least one amino acid modification (forexample, possessing 1, 2, 3, 4, 5, 6, 7, 8, 9, or more amino acidmodifications) relative to a wild-type Fc region, such that the moleculehas an enhanced effector function relative to a molecule comprising awild-type Fc region, optionally wherein the variant Fc region comprisesa substitution at any one or more of positions 221, 239, 243, 247, 255,256, 258, 267, 268, 269, 270, 272, 276, 278, 280, 283, 285, 286, 289,290, 292, 293, 294, 295, 296, 298, 300, 301, 303, 305, 307, 308, 309,310, 311, 312, 316, 320, 322, 326, 329, 330, 332, 331, 332, 333, 334,335, 337, 338, 339, 340, 359, 360, 370, 373, 376, 378, 392, 396, 399,402, 404, 416, 419, 421, 430, 434, 435, 437, 438 and/or 439.

Anti-NKp46 antibodies may comprise a variant Fc region, wherein thevariant Fc region comprises at least one amino acid modification (forexample, possessing 1, 2, 3, 4, 5, 6, 7, 8, 9, or more amino acidmodifications) relative to a wild-type Fc region, such that the moleculehas an enhanced effector function relative to a molecule comprising awild-type Fc region, optionally wherein the variant Fc region comprisesa substitution at any one or more of positions 329, 298, 330, 332, 333and/or 334 (e.g., S239D, S298A, A330L, 1332E, E333A and/or K334Asubstitutions). In one example, the residues at amino acid positionsS239 and 1332 may be substituted, for example by another amino acid,optionally wherein the S239 modification is an S239D substitution andthe 1332 modification is an 1332E substitution; such substitutedconstant regions provide increased binding to the activatory FcγRIIIA.

In one embodiment, antibodies having variant or wild-type Fc regions mayhave altered glycosylation patterns that increase Fc receptor bindingability of antibodies. Such carbohydrate modifications can beaccomplished by, for example, expressing the antibody in a host cellwith altered glycosylation machinery. Cells with altered glycosylationmachinery have been described in the art and can be used as host cellsin which to express recombinant antibodies to thereby produce anantibody with altered glycosylation. See, for example, Shields, R. L. etal. (2002) J. Biol. Chem. 277:26733-26740 and Umana et al. (1999) Nat.Biotech. 17:176-1, as well as European Patent No. EP 1,176,195 and PCTPublications WO 06/133148, WO 03/035835, and WO 99/54342, each of whichis incorporated herein by reference in its entirety.

Generally, such antibodies with altered glycosylation are“glyco-optimized” such that the antibody has a particular N-glycanstructure that produces certain desirable properties, including, but notlimited to, enhanced ADCC and effector cell receptor binding activitywhen compared to non-modified antibodies or antibodies having anaturally occurring constant region and produced by murine myeloma NSOand Chinese Hamster Ovary (CHO) cells (Chu and Robinson, Current OpinionBiotechnol. 2001, 12: 180-7), HEK293T-expressed antibodies as producedherein in the Examples section, or other mammalian host cell linescommonly used to produce recombinant therapeutic antibodies.

Monoclonal antibodies produced in mammalian host cells contain anN-linked glycosylation site at Asn297 of each heavy chain. Glycans onantibodies are typically complex biatennary structures with very low orno bisecting N-acetylglucosamine (bisecting GlcNAc) and high levels ofcore fucosylation. Glycan temini contain very low or no terminal sialicacid and variable amounts of galactose. For a review of effects ofglycosylation on antibody function, see, e.g., Wright & Morrison, TrendsBiotechnol. 15:26-31 (1997). Considerable work shows that changes to thesugar composition of the antibody glycan structure can alter Fc effectorfunctions. The important carbohydrate structures contributing toantibody activity are believed to be the fucose residues attached viaalpha-1,6 linkage to the innermost N-acetylglucosamine (GlacNAc)residues of the Fc region N-linked oligosaccharides (Shields et al.,2002).

Non-fucosylated oligosaccharide structures (at Asn297) have recentlybeen associated with dramatically increased in vitro ADCC activity. “Asn297” means amino acid asparagine located at about position 297 in the Fcregion; based on minor sequence variations of antibodies, Asn297 canalso be located some amino acids (usually not more than +3 amino acids)upstream or downstream.

Historically, antibodies produced in CHO cells contain about 2 to 6% inthe population that are nonfucosylated. YB2/0 (rat myeloma) and Lecl3cell line (a lectin mutant of the CHO line which has a deficientGDP-mannose 4,6-dehydratase leading to the deficiency of GDP-fucose orGDP sugar intermediates that are the substrate ofalpha6-fucosyltransferase) have been reported to produce antibodies with78 to 98% non-fucosylated species. In other examples, RNA interference(RNAi) or knock-out techniques can be employed to engineer cells toeither decrease the FUT8 mRNA transcript levels or knock out geneexpression entirely, and such antibodies have been reported to containup to 70% non-fucosylated glycan.

Anti-NKp46 antibodies may be glycosylated with a sugar chain at Asn297,said antibody showing increased binding affinity via its Fc portion toFcγRII. In one embodiment, an antibody will comprise a constant regioncomprising at least one amino acid alteration in the Fc region thatimproves antibody binding to FcγRIIIa and/or ADCC.

In one aspect, the antibodies are hypofucosylated in their constantregion. Such antibodies may comprise an amino acid alteration or may notcomprise an amino acid alteration but be produced or treated underconditions so as to yield such hypofucosylation. In one aspect, anantibody composition comprises a chimeric, human or humanized antibodydescribed herein, wherein at least 20, 30, 40, 50, 60, 75, 85, 90, 95%or substantially all of the antibody species in the composition have aconstant region comprising a core carbohydrate structure (e.g., complex,hybrid and high-mannose structures) which lacks fucose. In oneembodiment, an antibody composition is free of antibodies comprising acore carbohydrate structure having fucose. The core carbohydrate willpreferably be a sugar chain at Asn297.

In one embodiment an antibody composition, e.g., a compositioncomprising antibodies which bind to NKp46, is glycosylated with a sugarchain at Asn297, wherein the antibodies are partially fucosylated.Partially fucosylated antibodies are characterized in that theproportion of anti-NKp46 antibodies in the composition that lack fucosewithin the sugar chain at Asn297 is between 20% and 90%, preferablybetween 20% and 80%, preferably between 20% and 50%, 55%, 60%, 70% or75%, between 35% and 50%, 55%, 60%, 70% or 75%, or between 45% and 50%,55%, 60%, 70% or 75%. Preferably the antibody is of human IgG1 or IgG3type.

The sugar chain can further show any characteristics (e.g., presence andproportion of complex, hybrid and high-mannose structures), includingthe characteristics of N-linked glycans attached to Asn297 of anantibody from a human cell, or of an antibody recombinantly expressed ina rodent cell, murine cell (e.g., CHO cell) or avian cell.

In one embodiment, the antibody is expressed in a cell that is lackingin a fucosyltransferase enzyme such that the cell line produces proteinslacking fucose in their core carbohydrates. For example, the cell linesMs704, Ms705, and Ms709 lack the fucosyltransferase gene, FUT8 (alpha(1,6) fucosyltransferase), such that antibodies expressed in the Ms704,Ms705, and Ms709 cell lines lack fucose on their core carbohydrates.These cell lines were created by the targeted disruption of the FUT8gene in CHO/DG44 cells using two replacement vectors (see U.S. PatentPublication No. 20040110704 by Yamane et al. and Yamane-Ohnuki et al.(2004) Biotechnol Bioeng 87:614-22, the disclosures of which areincorporated herein by reference). Other examples have included use ofantisense suppression, double-stranded RNA (dsRNA) interference, hairpinRNA (hpRNA) interference or intron-containing hairpin RNA (ihpRNA)interference to functionally disrupt the FUT8 gene. In one embodiment,the antibody is expressed in a cell line with a functionally disruptedFUT8 gene, which encodes a fucosyl transferase, such that antibodiesexpressed in such a cell line exhibit hypofucosylation by reducing oreliminating the alpha 1,6 bond-related enzyme.

In one embodiment, the antibody is expressed in cell lines engineered toexpress glycoprotein-modifying glycosyl transferases (e.g.,beta(1,4)-N-acetylglucosaminyl-transferase III (GnTHI)) such thatantibodies expressed in the engineered cell lines exhibit increasedbisecting GlcNac structures which results in increased ADCC activity ofthe antibodies (PCT Publication WO 99/54342 by Umana et al. and Umana etal. (1999) Nat. Biotech. 17:176-180, the disclosures of which areincorporated herein by reference).

In another embodiment, the antibody is expressed and the fucosylresidue(s) is cleaved using a fucosidase enzyme. For example, thefucosidase alpha-L-fucosidase removes fucosyl residues from antibodies(Tarentino et al. (1975) Biochem. 14:5516-5523). In other examples, acell line producing an antibody can be treated with a glycosylationinhibitor; Zhou et al. (Biotech. and Bioengin. 99: 652-665 (2008))described treatment of CHO cells with the alpha-mannosidase I inhibitorkifunensine, resulting in the production of antibodies withnon-fucosylated oligomannose-type N-glucans.

In one embodiment, the antibody is expressed in a cell line whichnaturally has a low enzyme activity for adding fucosyl to theN-acetylglucosamine that binds to the Fc region of the antibody or doesnot have the enzyme activity, for example the rat myeloma cell lineYB2/0 (ATCC CRL 1662). Other example of cell lines include a variant CHOcell line, Led 3 cells, with reduced ability to attach fucosyl toAsn(297)-linked carbohydrates, also resulting in hypofucosylation ofantibodies expressed in that host cell (WO 2003/035835 (Presta et al)and Shields, R. L. et al. (2002) J. Biol. Chem. 277:26733-26740, thedisclosures of which are incorporated herein by reference). In anotherembodiment, the antibody is expressed in an avian cell, preferably anEBx® cell (Vivalis, France) which naturally yields antibodies with lowfucose content, e.g., WO 2008/142124. Hypofucosylated glycans can alsobe produced in cell lines of plant origin, e.g., WO 2007/084926 (BiolexInc.) and WO 2008/006554 (Greenovation Biotech GMBH), the disclosures ofwhich are incorporated herein by reference.

Antibody Formulations

Pharmaceutically acceptable carriers that may be used in thesecompositions include, but are not limited to, ion exchangers, alumina,aluminum stearate, lecithin, serum proteins, such as human serumalbumin, buffer substances such as phosphates, glycine, sorbic acid,potassium sorbate, partial glyceride mixtures of saturated vegetablefatty acids, water, salts or electrolytes, such as protamine sulfate,disodium hydrogen phosphate, potassium hydrogen phosphate, sodiumchloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinylpyrrolidone, cellulose-based substances, polyethylene glycol, sodiumcarboxymethylcellulose, polyacrylates, waxes,polyethylene-polyoxypropylene-block polymers, polyethylene glycol andwool fat. The antibodies may be employed in a method of eliminating,inhibiting or depleting, the activity of NKp46-expressing PTCL cells ina patient. This method comprises the step of administering saidcomposition to said patient. Such method will be useful for bothprophylaxis and therapeutic purposes.

For use in administration to a patient, the composition will beformulated for administration to the patient. The compositions may beadministered orally, parenterally, by inhalation spray, topically,rectally, nasally, buccally, vaginally or via an implanted reservoir.The techniques used herein include subcutaneous, intravenous,intramuscular, intra-articular, intra-synovial, intrasternal,intrathecal, intrahepatic, intralesional and intracranial injection orinfusion techniques.

Sterile injectable forms of the compositions may be aqueous or anoleaginous suspension. These suspensions may be formulated according totechniques known in the art using suitable dispersing or wetting agentsand suspending agents. The sterile injectable preparation may also be asterile injectable solution or suspension in a non-toxic parenterallyacceptable diluent or solvent, for example as a solution in1,3-butanediol. Among the acceptable vehicles and solvents that may beemployed are water, Ringer's solution and isotonic sodium chloridesolution. In addition, sterile, fixed oils are conventionally employedas a solvent or suspending medium. For this purpose, any bland fixed oilmay be employed including synthetic mono- or diglycerides. Fatty acids,such as oleic acid and its glyceride derivatives, are useful in thepreparation of injectables, as are natural pharmaceutically-acceptableoils, such as olive oil or castor oil, especially in theirpolyoxyethylated versions. These oil solutions or suspensions may alsocontain a long-chain alcohol diluent or dispersant, such ascarboxymethyl cellulose or similar dispersing agents that are commonlyused in the formulation of pharmaceutically acceptable dosage forms,including emulsions and suspensions. Other commonly used surfactants,such as Tweens, Spans and other emulsifying agents or bioavailabilityenhancers which are commonly used in the manufacture of pharmaceuticallyacceptable solid, liquid, or other dosage forms, may also be used forthe purposes of formulation.

Several monoclonal antibodies have been shown to be efficient inclinical situations, such as Rituxan™ (Rituximab), Herceptin™(Trastuzumab) or Xolair™ (Omalizumab), and similar administrationregimens (i.e., formulations and/or doses and/or administrationprotocols) may be used with the antibodies that bind NKp46. For example,an antibody present in a pharmaceutical composition can be supplied at aconcentration of 10 mg/mL in either 100 mg (10 mL) or 500 mg (50 mL)single-use vials. The product is formulated for IV administration in 9.0mg/mL sodium chloride, 7.35 mg/mL sodium citrate dihydrate, 0.7 mg/mLpolysorbate 80, and Sterile Water for Injection. The pH is adjusted to6.5. An exemplary suitable dosage range for an antibody in apharmaceutical composition may between about 1 mg/m² and 500 mg/m².However, it will be appreciated that these schedules are exemplary andthat an optimal schedule and regimen can be adapted taking into accountthe affinity and tolerability of the particular antibody in thepharmaceutical composition that must be determined in clinical trials. Apharmaceutical composition for injection (e.g., intramuscular, i.v.)could be prepared to contain sterile buffered water (e.g., 1 ml forintramuscular), and between about 1 ng to about 100 mg, e.g., about 50ng to about 30 mg or, more preferably, about 5 mg to about 25 mg, of ananti-NKp46 antibody.

According to another embodiment, the antibody compositions may furthercomprise another therapeutic agent, including agents normally utilizedfor the particular therapeutic purpose for which the antibody is beingadministered, notably for the treatment of a PTCL. The additionaltherapeutic agent will normally be present in the composition in amountstypically used for that agent in a monotherapy for the particulardisease or condition being treated. Such therapeutic agents include, butare not limited to, anti-inflammation agents, steroids, immune systemsuppressors, antibiotics, antivirals and other antibodies and fragmentsthereof.

Diagnosis and Treatment of Malignancies

Methods useful in the diagnosis, prognosis and monitoring of aperipheral T-cell lymphoma in an individual are described. In oneembodiment, the methods comprise determining the level of expression ofan NKp46 nucleic acid or polypeptide in a biological sample from apatient, e.g., in tumor cells found in a biological sample (e.g., abiopsy). In one embodiment, the methods comprise determining the levelof expression of an NKp46 nucleic acid or polypeptide in a biologicalsample and comparing the level to a reference level (e.g., a value, weakcell surface staining, etc.) corresponding to a healthy individual. Adetermination that a biological sample expresses an NKp46 nucleic acidor polypeptide at a level that is increased compared to the referencelevel indicates that the patient has a peripheral T-cell lymphoma, e.g.,an NKp46-positive peripheral T-cell lymphoma. Optionally, detecting anNKp46 polypeptide in a biological sample comprises detecting the NKp46polypeptide expressed on the surface of a lymphocyte.

In one embodiment, the methods comprise: (a) determining whether anindividual has a peripheral T-cell lymphoma; and (b) if the individualhas a peripheral T-cell lymphoma, determining whether the individual hasperipheral T-cell lymphoma cells that express an NKp46 polypeptide.

Also provided is a method for the assessment of the development level ofa PTCL (staging disease) permitting the evaluation of the proportion(e.g., percentage) of malignant PTCL cells present within a certain bodycompartment of a patient. According to this method, cells from abiological sample collected from said body compartment are brought intocontact with an anti-NKp46 antibody and tumor (PTCL) cells (e.g., theproportion of cells) expressing an NKp46 polypeptide at their surface ismeasured. The cells may be, for example, CD4+ cells or CD4-CD8+ cells. Afinding that tumor cells express NKp46, e.g., predominantly expressNKp46, may be used to indicate that the PTCL is an aggressive oradvanced PTCL (e.g., stage IV, or more generally beyond stage II).

Also provided is a method for PTCL diagnosis, comprising bringing cellsfrom a biological sample from an individual into contact with ananti-NKp46 antibody and measuring the proportion (e.g., percentage) of Tcells expressing an NKp46 polypeptide at their surface, and comparingsuch proportion to the average proportion (e.g., percentage) of T cellsexpressing an NKp46 polypeptide at their surface observed in non-PTCLhumans (preferably in healthy humans), wherein a PTCL-positive diagnosisis made when said measured proportion is significantly higher than saidaverage proportion.

Also provided are therapeutic methods for treating individuals having aPTCL, susceptible to a PTCL or having experienced a PTCL, wherein thetreatment involves administering anti-NKp46 antibodies, anti-NKp46antibody compositions, and/or related compositions to an individualhaving or susceptible to PTCL. In one embodiment, the PTCL is anaggressive or advanced PTCL (e.g., stage IV, or more generally beyondstage II). In one embodiment, the PTCL is a non-cutaneous PTCL. In oneembodiment, the PTCL is an aggressive T-cell lymphoma. In oneembodiment, the patient has relapsing or refractory disease. In oneembodiment, the patient has a poor prognosis for disease progression(e.g., poor prognosis for survival) or has a poor prognosis for responseto a therapy.

In one embodiment, the PTCL is an aggressive T-cell neoplasm. In oneembodiment, the PTCL is an aggressive T-cell neoplasm. In oneembodiment, the PTCL is an aggressive non-cutaneous PTCL. In oneembodiment, the PTCL is an aggressive cutaneous PTCL, optionally aprimary cutaneous CD4+ small/medium T-cell lymphoma or a primary CD8+small/medium T-cell lymphoma. PTCL and PTCL-NOS as used herein excludethe cutaneous T-cell lymphomas Sezary Syndrome and mycosis fungoides,which are considered distinct pathologies.

In one embodiment, the PTCL is a nodal (e.g., primarily or predominantlynodal) PTCL. Predominantly nodal PTCLs include PTCL-NOS (PeripheralT-cell lymphomas, not otherwise specified), anaplastic large celllymphomas (ALCL) and angioimmunoblastic T-cell lymphomas (AITL). Forexample a PTCL may be an aggressive, non-cutaneous, predominantly nodalPCTL (the disease may additionally have extra-nodal presentation).

In one embodiment, the PTCL is an extranodal (e.g., primarilyextranodal) PTCL. For example a PTCL may be an aggressive,non-cutaneous, extranodal PCTL.

In one embodiment, the PTCL is an adult T-cell leukemia or lymphoma(ATL), e.g., an HTLV+ ATL.

In one embodiment, the PTCL is an orthovisceral extranodal PTCL. In oneembodiment, the PTCL is an extranodal NK−/T-cell lymphoma, nasal type.In one embodiment, the PTCL is an enteropathy-associated T-celllymphoma.

In one embodiment, the PTCL is an anaplastic large cell lymphoma (ALCL),optionally an ALK+ ALCL, optionally an ALK− ALCL. ALK+ ALCL generallyenjoys favorable prognostics using conventional therapy (93% 5-yearsurvival) but ALK− ALCL has poor prognostics (37%). ALCL is generallycharacterized by uniform CD30 surface expression. Anti-NKp46 antibodiescan therefore be used in combination with anti-CD30 antibodies (e.g.,Adcetris™ (brentuximab vedotin, Seattle Genetics, Inc.)), for thetreatment of ALCL. ALCL is generally also CD4+, although with occasionalCD4-CD8+ cases. Anti-NKp46 antibodies can therefore be used incombination with anti-CD4 antibodies to treat ALCL.

In one embodiment, the PTCL is an angioimmunoblastic T-cell lymphoma(AITL), optionally a cutaneous AITL, optionally a primary cutaneous CD4+small/medium T-cell lymphoma or a primary CD8+ small/medium T-celllymphoma, optionally a non-cutaneous AITL.

In one embodiment, the PTCL is an intestinal lymphoma, e.g., anintestinal ALCL.

In one embodiment, the PTCL is a T-cell prolymphocytic leukemia.

In one embodiment, a PTCL is a PTCL-NOS (Peripheral T-cell lymphoma, nototherwise specified). PTCL-NOS, also referred to as PCTL-U orPTCL-unspecified, are aggressive lymphomas, mainly of nodal type, butextranodal involvement is common. The majority of nodal cases are CD4+and CD8-, and CD30 can be expressed in large cell variants. Mostpatients with PTCL-NOS present with nodal involvement; however, a numberof extranodal sites may also be involved (e.g., liver, bone marrow,gastrointestinal, skin). Studies generally report a 5-year overallsurvival of approximately 30%-35% using standard chemotherapy. In thepast, a number of definite entities corresponding to recognizablesubtypes of T-cell neoplasm, such as Lennert lymphoma, T-zone lymphoma,pleomorphic T-cell lymphoma, small and medium-sized and large-cellT-cell lymphoma, and T-immunoblastic lymphoma have been described, butevidence that these correspond to distinctive clinicopathologicalentities is still lacking. For this reason the recent World HealthOrganization (WHO) classification of the hematopoietic and lymphoidneoplasms has collected these under the single broad category ofPTCL-NOS/U. PTCL-NOS may therefore be specified to exclude certaindistinctive clinicopathological entities such as T-cell prolymphocyticleukemia, aggressive NK-cell leukemia, ATL/adult T-cell leukemia,extranodal NK−/T-cell leukemia nasal type, EATL/enteropathy-type T-celllymphoma, hepatosplenic T-cell lymphoma, subcutaneous panniculitis-likeT-cell lymphoma, ALCL/anaplastic large-cell lymphoma, and/orAITL/angioimmunoblastic T-cell lymphoma. Anti-NKp46 antibodies cantherefore be used in combination with anti-CD4 antibodies to treatPTCL-NOS. Anti-NKp46 antibodies can therefore be used in combinationwith anti-CD30 antibodies to treat PTCL-NOS that are CD30+.

PTCL diagnosis criteria can be those of standard medical guidelines, forexample, according to the World Health Organization (WHO) classificationsystem (see, e.g., World Health Organization, WHO Classification ofTumours of Haematopoietic and Lymphoid Tissues, 4^(th) ed. Lyon, France:IARC Press, 2008). See also, e.g., Foss et al. (2011) Blood117:6756-6767, the disclosures of which are incorporated herein byreference.

In one exemplary aspect, a method is provided of reducing progression ofPTCL in a mammalian host, (e.g., a human patient) having a detectablelevel of cancer cells, comprising administering an anti-NKp46 antibody,an anti-NKp46 antibody composition, or a related composition (e.g., anucleic acid encoding an anti-NKp46 antibody) in an amount sufficient todetectably reduce the progression of the hematological malignancies inthe host.

In one exemplary aspect, a method is provided of treating PTCL in anindividual having a poor disease prognosis and/or who has relapsed, isresistant or is not responsive to therapy with a first therapeuticagent.

Disease or cancer diagnosis and progression can be defined by standardcriteria for the particular type of disease. PTCL (e.g., PTCL-NOS) istypically based on examination of peripheral blood or tissue biopsy forhistological features supplemented by detailed immunohistochemistry,flow cytometry, cytogenetics and molecular genetics. Examination mayinclude, for example, full blood count and differential tests of renaland hepatic function, lactate dehydrogenase (LDH), Beta2 microglobulin,albumin, serum calcium, uric acid, bone marrow biopsy, chest X-ray andcomputerized tomography (CT) scan of chest, abdomen and pelvis.Progression is optionally determined by assessing the selective clonalexpansion of initiated cells. Methods for detecting cancers and cancerprogression can be achieved by any suitable technique, several examplesof which are known in the art. Examples of suitable techniques includePCR and RT-PCR (e.g., of cancer cell-associated genes or “markers”),biopsy, imaging techniques, karyotyping and other chromosomal analysis,immunoassay/immunocytochemical detection techniques, histological and/orhistopathology assays, cell kinetic studies and cell cycle analysis,flow cytometry, and physical examination techniques (e.g., for physicalsymptoms).

In one embodiment, diagnosing or assessing PTCL (e.g., PTCL-NOS)comprises chromosomal analysis. Cases of PTCL-NOS often showheterogeneous, variable morphology, with losses having been reported in3q, 6q, 9p, 10q, 12q and/or 5q, and recurrent chromosomal gains,including in 8q, 9p and/or 19q. One CGH study in PTCL-NOS has shownfrequent gains of 7q22-31, 1q, 3p, 5p and 8q24qter and losses of 6q22-24and 10p13pter and cases with complex karyotypes had poor diseaseprognosis.

In one embodiment, diagnosing or assessing PTCL comprises biomarkeranalysis. In one embodiment, a patient having a poor disease prognosisis identified by biomarker analysis wherein the presence or absence(e.g., level of) a nucleic acid or protein is detected in a biologicalsample from the patient (e.g., in tumor cells from a patient). A rangeof biomarkers are known in PTCL, including, e.g., p53, Ki-67, BCL-2,BCL-XL, CD26, EBV, MDR, CCND2, CCR4, NK-Kb, CCR3, CXCR3, PRDM1, andALK−1.

In one embodiment, diagnosing or assessing PTCL comprises detectingchemokine receptors CXCR3 and/or CCR4 (e.g., detecting the presence orabsence of CXCR3 and/or CCR4 nucleic acid or proteins, or levels ofCXCR3 and/or CCR4 nucleic acid or proteins). CXCR3 and CCR4 have beenfound respectively in 63% and 34% of PTCL-NOS (Percy et al., Int. ClassDiseases for Oncol. (ICD-O-3), 3^(rd) ed. Geneva, Switzerland: WorldHealth Organization (2000)). In one embodiment, a determination that apatient has a PTCL (e.g., PTCL cells) that is CXCR3-positive andCCR4-negative indicates that the patient has a poor disease prognosis.

In one embodiment, enteropathy-type T-cell lymphoma is diagnosed and/ortreated with an anti-NKp46 antibody composition. Enteropathy-associatedT-cell lymphoma (EATL) is considered a complication of celiac disease(CD); see, e.g., Di Sabatino et al. (2012) Blood 119:2458-2468. Thistumor derives from the neoplastic transformation of aberrantintraepithelial T lymphocytes emerging in celiac patients unresponsiveto a gluten-free diet. Poor adherence to a gluten-free diet, HLA-DQ2homozygosity, and late diagnosis of CD are recognized as risk factorsfor malignant evolution of CD. Refractory CD (RCD) often progresses toEATL. Diagnosing or assessing EATL may thus comprise detecting a markerof EATL, or of CD or RCD that is susceptible to progressing to EATL, oridentifying a patient as having EATL, or CD or RCD susceptible toprogressing to EATL. In one embodiment, enteropathy-type T-cell lymphomais treated with (by administering) an anti-NKp46 antibody composition,in combination with a second therapeutic agent used in the treatment ofEATL, e.g., a chemotherapy, e.g., CHOP comprising cyclophosphamide,doxorubicin, vincristine, prednisone, or other multi-chemotherapeuticagent regimens.

Delivering anti-NKp46 antibodies to a subject (either by directadministration or expression from a nucleic acid therein, such as from apox viral gene transfer vector comprising anti-NKp46 antibody-encodingnucleic acid sequence(s)) and practicing the other methods herein can beused to reduce, treat, prevent, or otherwise ameliorate any suitableaspect of cancer progression (notably PTCL progression). The methods canbe particularly useful in the reduction and/or amelioration of tumorgrowth (e.g., percentage (tumor cells compared to healthy T cells),number of tumor cells in circulation), and any parameter or symptomassociated therewith (e.g., biomarkers). Methods that reduce, prevent,or otherwise ameliorate such aspects of cancer progression,independently and collectively, are advantageous features.

In another aspect, a method is provided of reducing the risk of cancerprogression, reducing the risk of further cancer progression in a cellpopulation that has undergone initiation, and/or providing a therapeuticregimen for reducing cancer progression in a human patient, whichcomprises administering to the patient one or more first treatments(e.g., induction therapy, such as a chemotherapeutic agent or anantibody) in an amount and regimen sufficient to achieve a response(partial or complete response), and then administering an amount of ananti-NKp46 antibody or related composition (or applying a combinationadministration method) to the patient.

In a further aspect, a method is provided of promoting remission of aPTCL in a mammalian host, such as a human patient, comprisingadministering a composition comprising an anti-NKp46 antibody to thehost, so as to promote PTCL remission in the host.

In an even further aspect, a method is provided for reducing the risk ofdeveloping a PTCL, reducing the time to onset of a cancerous condition,and/or reducing the severity of a PTCL diagnosed in the early stages,comprising administering to a host a prophylactically effective amountof an anti-NKp46 antibody or related composition so as to achieve thedesired physiological effect(s).

In a further aspect, a method is provided of increasing the likelihoodof survival over a relevant period in a human patient diagnosed withPTCL. In another aspect, a method is provided for improving the qualityof life of a PTCL patient, comprising administering to the patient acomposition in an amount effective to improve the quality of lifethereof. In a further aspect, methods described herein can be applied tosignificantly reduce the number of PTCL cells in a vertebrate host, suchthat, for example, the total number of PTCL cells is reduced. In arelated sense, a method is provided for killing (e.g., either directlyor indirectly causing the death of) PTCL cells in a vertebrate, such asa human cancer patient.

According to another embodiment, the antibody compositions may be usedin combined treatments with one or more other therapeutic agents,including agents normally utilized for the particular therapeuticpurpose for which the antibody is being administered, notably for thetreatment of a PTCL. The additional therapeutic agent will normally beadministered in amounts and treatment regimens typically used for thatagent in a monotherapy for the particular disease or condition beingtreated. Such therapeutic agents include, but are not limited to,anti-inflammation agents, steroids, immune system suppressors,antibiotics, antivirals and other antibodies and fragments thereof.

For example, a second therapeutic agent may include one or morechemotherapeutic drugs, tumor vaccines, antibodies, etc. Furtheranti-cancer agents include alkylating agents, cytotoxic antibiotics suchas topoisomerase I inhibitors, topoisomerase II inhibitors, plantderivatives, RNA/DNA antimetabolites, and antimitotic agents. Examplesmay include, for example, cisplatin (CDDP), carboplatin, procarbazine,mechlorethamine, cyclophosphamide, camptothecin, ifosfamide, melphalan,chlorambucil, busulfan, nitrosurea, dactinomycin, daunorubicin,doxorubicin, bleomycin, plicomycin, mitomycin, etoposide (VP16),tamoxifen, raloxifene, taxol, gemcitabine, navelbine, transplatinum,5-fluorouracil, vincristine, vinblastine and methotrexate, or any analogor derivative variant of the foregoing.

Drugs currently used or tested for the treatment of PTCL include, interalia, chemotherapeutic agents such as CHOP (cyclophosphamide,doxorubicin, vincristine and prednisone), anthracycline, antifolates,conjugates such as anti-CD25 fused to pseudomonas toxin, IL-2 targetingdomain fused with diphtheria toxin, and anti-CD30 antibody conjugated toauristatins (monomethylauristatin-E), HDAC inhibitors, lenalidomide,monoclonal antibodies such as anti-CD52, anti-VEGF (bevacizumab),anti-CD30 (adcetris), anti-CCR4, anti-CD4 (e.g., zanolimumab) andanti-CD2, nucleoside analogues such as cladribine, clofarabine,fludarabine, gemcitabine, nelarabine and pentostatin, proteosomeinhibitors such as bortezomib and signaling inhibitors such as selectiveinhibitors of protein kinase C (e.g., enzastaurin) or syk inhibitors(e.g., R788).

In the treatment methods, the NKp46-binding compound and the secondtherapeutic agent can be administered separately, together orsequentially, or in a cocktail. In some embodiments, the antigen-bindingcompound is administered prior to the administration of the secondtherapeutic agent. For example, the NKp46-binding compound can beadministered approximately 0 to 30 days prior to the administration ofthe second therapeutic agent. In some embodiments, an NKp46-bindingcompound is administered from about 30 minutes to about 2 weeks, fromabout 30 minutes to about 1 week, from about 1 hour to about 2 hours,from about 2 hours to about 4 hours, from about 4 hours to about 6hours, from about 6 hours to about 8 hours, from about 8 hours to 1 day,or from about 1 to 5 days prior to the administration of the secondtherapeutic agent. In some embodiments, an NKp46-binding compound isadministered concurrently with the administration of the therapeuticagents. In some embodiments, an NKp46-binding compound is administeredafter the administration of the second therapeutic agent. For example,an NKp46-binding compound can be administered approximately 0 to 30 daysafter the administration of the second therapeutic agent. In someembodiments, an NKp46-binding compound is administered from about 30minutes to about 2 weeks, from about 30 minutes to about 1 week, fromabout 1 hour to about 2 hours, from about 2 hours to about 4 hours, fromabout 4 hours to about 6 hours, from about 6 hours to about 8 hours,from about 8 hours to 1 day, or from about 1 to 5 days after theadministration of the second therapeutic agent.

EXAMPLES Example 1—Anti-NKp46 mAbs are Capable of Directing ADCC TowardNKp46+ Cells

Antibody 195314, mlgG2b, available commercially from R&D Systems, Inc.(Minneapolis, USA) was tested for the ability to mediate ADCC towardsthe 721.221 EBV transfected B cell line transfected with human NKp46, incomparison with anti-CD20 antibody rituximab.

Briefly, the cytolytic activity of human NK cell line KHYG-1 transfectedwith murine FcγRIV was assessed in a classical 4-h ³¹Cr-release assay in96-well plates from Greiner. Briefly, 721.221 cells were labelled with⁵¹Cr (100 ρCi (3.7 MBq)/1×10⁶ cells), then mixed with KHYG-1 transfectedwith murine FcγRIV (to bind mlgG2b) at an effector/target ratio equal to20, in the presence of antibody at indicated concentrations. After briefcentrifugation and 4 hours of incubation at 37° C., 50 μL supernatantwere removed, and the ⁵¹Cr release was measured with a TopCount NXT betadetector (PerkinElmer Life Sciences, Boston, Mass.). All experimentalgroups were analyzed in triplicate, and the percentage of specific lysiswas determined as follows: 100×(mean cpm experimental release−mean cpmspontaneous release)/(mean cpm total release−mean cpm spontaneousrelease). Percentage of total release was obtained by lysis of targetcells with 2% Triton X100 (Sigma).

Antibody 195314 (as well as positive control rituximab) induced specificlysis of NKp46-tranfected 721.221 cells by human KHYG-1 murine FcγRIV NKcell lines, thereby showing that these anti-NKp46 antibodies induce ADCCtoward NKp46-expressing target cells (FIG. 1). We therefore show thatantiNKp46 antibodies with constant regions that bind to activating Fcreceptors can lead to depletion of NKp46-expressing tumor cells, andmoreover despite KHYG-1 NK cells themselves expressing NKp46 at theirsurface.

Example 2—NKp46 is Expressed in PTCL

Tumor biopsies were obtained and staining was performed on frozensamples. NKp46 was detected with anti-human NKp46 antibody clone “9E2”(mlgG1), Becton Dickinson, Franklin Lakes, N.J., USA, product ref.557911, by DAB chromogenic detection according to standard protocols,adapted for immunostaining with BenchMark XT, Ventana Roche. For allstaining control isotype (mlgG1) and control DAB were performed. CD30was additionally stained. Tumors 3, 4 and 5 were from the same patient.Tumors 1-5 were from patients having PTCL not otherwise specified.Tumors 6-8 are mycosis fungoides samples, a cutaneous T cell lymphoma(CTCL).

Tumor characteristics are shown in Table A. Results are shown in TableB. PTCL from each of the samples from the patient from whom tumorsamples 3, 4 and 5 were obtained had strong membranar staining, with ahigh percentage of cells being NKp46 positive. The patient from whomsamples 3-5 were obtained had advanced (stage IV) disease. On the otherhand, samples 1, 2, 6, 7 and 8 representing less advanced disease (stageI or II) all had either no staining or low percentages of NKp46+ tumorcells. Consequently, while some tumors are capable of expressing NKp46at high levels and are thus suitable for targeting with an NKp46 bindingagent, tumor cells may acquire the NK marker NKp46 at more advancedstages of disease, or more aggressive disease. NKp46 may therefore be aparticularly suitable target for treatment of advanced disease, or forpreventing progression of disease to advanced stages. Additionally,treatment of earlier stage disease with an NKp46 binding agent maybenefit from diagnostic (e.g., theranostic) assays to identify patientshaving prominent expression of NKp46 on the surface of tumor cells. TheNKp46 positive tumors were CD30-negative; NKp46 may thereforefurthermore represent a therapeutic target when anti-CD30 antibodiescannot be used (or when tumors are resistant to anti-CD30 antibody).

Example 3—NKp46 is Expressed in Samples from ALCL and Ortho VisceralExtranodal Disease (NK/T-Lymphoma and EATL)

MEC04 and SNK6 NK/T-lymphoma cells were stained for NKp46 expressionusing flow cytometry (FACS), together with characterization of variouscell surface markers. NKp46 was stained with anti-NKp46 antibody linkedto phycoerythrin (PE). Additional markers evaluated were hCD56 PE,hCD183/CXCR3 PE, hCD3 PE, hCD4 PE, hCD8 PE and CD54/ICAM PE. Cells wereharvested and stained using PE-labeled antibodies. After two washes,stainings were acquired on a BD FACSCanto II and analyzed using theFlowJo software.

Results are shown in FIG. 2. Anti-NKp46 antibody showed staining on theMEC04 and SNK6 cells, although with greater expression on SNK6. MEC04and SNK6 cells were additionally strongly stained with CD183 (CXCR3),CD56 and CD54 (ICAM), but not CD3, CD4 or CD8 (the most common phenotypeof extranodal NK/T-lymphomas are surface CD3- and CD56+).

We show that NK/T lymphoma cells, and in particular extranodal NK/T-celllymphoma, nasal type, can express NKp46, thereby providing thepossibility to treat NK/T-lymphoma with anti-NKp46 antibodies.Additionally, NKp46-positive NK/T-lymphoma tumors were found to expressCD183 (CXCR3), CD56 and CD54 (ICAM), which may permit administration ofanti-NKp46 in poor-prognosis patients, notably those having CXCR3expression typically associated with poor disease prognosis.

Studies were then carried out by immunohistochemistry (IHC) to provideconfirmation on patient samples and for different indications, bystaining primary tumor cells from human patients in frozen tissuesections with labeled anti-NKp46 antibody. Briefly, cell lines known tobe positive and negative for NKp46 expression were used as positive andnegative controls, respectively. Next, frozen hematopoietic tissuessections from healthy donors were stained for NKp46 expression, all ofwhich were negative for NKp46 expression. In NK/T lymphomas, nasal type,6 patient samples were tested, of which 5 samples were interpretable.All 5 interpretable samples were positively stained, confirming thatNK/T-lymphomas express NKp46. In samples from patients diagnosed withenteropathy-associated T-cell lymphoma (EATL), of 6 patient samples, 5samples were interpretable, of which in turn 2 were positively stainedand 3 were negative for staining, confirming that EATL cells can expressNKp46. In samples from patients diagnosed with anaplastic large celllymphoma (ALCL), of 4 interpretable patient samples, 3 were positivelystained and 1 was negative for staining, confirming that ALCL cells canexpress NKp46. Of the ALCL that stained positive for NKp46, 2 sampleswere ALK+ while one was ALK−.

TABLE A Tumor stage % % % Sample Tissue type Appearance Pathologydiagnosed (minimum) normal % lesion tumor necrosis 1 Lymphoidtissue/lymphatic Tumoral PTCL (unspecified) I 5 0 90 0 ganglion 2Lymphoid tissue/testicle Tumoral PTCL-NOS (unspecified) IE 10 0 60 0 3Lymphoid tissue/spleen Tumoral PTCL-NOS (unspecified) IV 10 0 40 0 4Lymphoid tissue/spleen Tumoral PTCL-NOS (unspecified) IV 5 0 90 0 5Lymphoid tissue/spleen Tumoral PTCL-NOS (unspecified) IV 50 0 50 0 6Lymphoid tissue/lymphatic Tumoral Mycosis fungoides II 0 0 70 20ganglion 7 Lymphoid tissue/lymphatic Tumoral Mycosis fungoides II 0 0 8010 ganglion 8 Lymphoid tissue/lymphatic Tumoral Mycosis fungoides II 0 080 10 ganglion

TABLE B Tumor 2: Tumor 3: Tumor 4: Tumor 5: Tumor 1: testis spleenspleen spleen Tumor 6: Tumor 7: Tumor 8: LN Lymphoma Lymphoma LymphomaLymphoma LN LN LN Lymphoma peripheral peripheral T peripheral Tperipheral T peripheral T Mycosis Mycosis Mycosis T cells cells cellscells cells fungoides fungoides fungoides NKp46 Negative 20% positive70% positive 80% 70-80% 10% faintly 10% faintly <5% faintly Stainingpositive positive positive positive positive NKp46 Less than 2% positiveLow intensity Membrane and Membrane Membrane Faint Faint Faint Stainedcells. Membrane and membrane and paranuclear dot staining stainingmembrane membrane membrane areas/ paranuclear dot paranuclear dotstaining staining + staining + staining comments staining of lowstaining diffused and diffused and intensity (probably fuzzy focal fuzzyfocal infiltrating NK cells) staining staining CD30 30% positiveNegative Negative Negative Negative 95% positive 95% positive 95%Staining positive CD30 paranuclear dot Cytoplasmic Membrane and MembraneStained staining with cytoplasmic and areas/ paranuclear withcytoplasmic comments dot staining paranuclear dot with stainingparanuclear dot staining

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference in theirentirety and to the same extent as if each reference were individuallyand specifically indicated to be incorporated by reference and were setforth in its entirety herein (to the maximum extent permitted by law),regardless of any separately provided incorporation of particulardocuments made elsewhere herein.

The use of the terms “a”, “an”, “the” and similar referents in thecontext of describing the invention are to be construed to cover boththe singular and the plural, unless otherwise indicated herein orclearly contradicted by context.

Unless otherwise stated, all exact values provided herein arerepresentative of corresponding approximate values (e.g., all exactexemplary values provided with respect to a particular factor ormeasurement can be considered to also provide a correspondingapproximate measurement, modified by “about,” where appropriate).

The description herein of any aspect or embodiment of the inventionusing terms such as “comprising”, “having”, “including”, or “containing”with reference to an element or elements is intended to provide supportfor a similar aspect or embodiment of the invention that “consists of”,“consists essentially of”, or “substantially comprises” that particularelement or elements, unless otherwise stated or clearly contradicted bycontext (e.g., a composition described herein as comprising a particularelement should be understood as also describing a composition consistingof that element, unless otherwise stated or clearly contradicted bycontext).

The use of any and all examples or exemplary language (e.g., “such as”)provided herein is intended merely to better illuminate the inventionand does not impose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

We claim:
 1. A method for treating a peripheral T cell lymphoma (PTCL)in an individual, the method comprising administering to an individual atherapeutically active amount of a compound that binds an NKp46polypeptide and depletes NKp46-expressing tumor cells.
 2. The method ofclaim 1, wherein the individual has an orthovisceral extranodal PTCL. 3.The method of claim 2, wherein the orthovisceral extranodal disease isNK/T-lymphoma.
 4. The method of claim 2, wherein the orthovisceralextranodal disease is enteropathy associated T cell lymphoma (EATL). 5.The method of claim 1, wherein the individual has refractory celiacdisease (RCD).
 6. The method of claim 1, wherein the PTCL is NK/Tlymphoma, nasal type, and wherein the method does not require a step ofdetermining the NKp46 polypeptide status of malignant cells within theindividual prior to administration of a compound that binds an NKp46polypeptide.
 7. The method of claim 1, wherein the treatment of a PTCLin an individual comprises: a) determining the NKp46 polypeptide statusof malignant cells within the individual having a PTCL, and b) upon adetermination that the individual has an NKp46 polypeptide prominentlyexpressed on the surface of malignant cells, administering to theindividual said compound that binds an NKp46 polypeptide.
 8. The methodof claim 1, wherein the compound that binds an NKp46 polypeptide is ananti-NKp46 antibody.
 9. The method of claim 1, wherein the antibodycomprises an amino acid modification that enhances binding to a humanFcγ receptor.
 10. The method of claim 1, wherein the antibody is linkedto a toxic agent.
 11. A method for detecting in an individual aperipheral T cell lymphoma (PTCL) selected from the group consisting ofNK/T-lymphoma, enteropathy associated T cell lymphoma (EATL) andrefractory celiac disease (RCD) susceptible to progressing to EATL, themethod comprising detecting an NKp46 nucleic acid or polypeptide in abiological sample from an individual.
 12. The method of claim 11,wherein detecting an NKp46 polypeptide in a biological sample comprisesdetecting NKp46 polypeptide expressed on the surface of a malignantlymphocyte.
 13. The method of claim 11, wherein an NKp46 polypeptide isdetected, and wherein said detecting an NKp46 polypeptide comprisesobtaining a biological sample from the individual that comprisesNK/T-lymphoma cells, EATL cells or refractory celiac disease cells,bringing said cells into contact with an antibody that binds an NKp46polypeptide, and detecting whether cells express NKp46 on their surface.14. The method of claim 11, wherein the individual has NK/T-lymphoma.15. The method of claim 11, wherein the individual has EATL.
 16. Themethod of claim 11, wherein the individual has RCD.